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UNIVERSITY  OF  ILLINOIS 


Agricultural  Experiment  Station 


BULLETIN  No.  114 


BY  JOHN  W. 


URBANA,  ILLINOIS,  MARCH,   1907 


SUMMARY  OF  BULLETIN  No.    114 

1.  Studies  of  apple  blossoms  in  reference  to  time  of  opening,  falling  of 
petals  and  closing-  of  calyxes,  indicate  that  the  first  application  of  spraying 
material  for  the  codling  moth  should  be  timed  with  reference  to  the  young 
apples  most  advanced  in  development  rather  than  to  the  average   develop- 
ment of  the  entire  setting  of  fruit  or  the  belated  specimens.  Page  377 

2.  A  test  of  different  methods  of  applj'ing  spraying  material  indicated 
that  the  most  effective  distribution  for  the  control  of  the  first  brood  of  the 
codling  moth  could  be  secured  by  the  use  of  a  Vermorel  nozzle  under  high 
pressure,  and  appl)ring  a  comparatively  large  amount  of  material.     Page  382 

3.  Although  one  thorough  application  of  spraying  material  at  the  proper 
time  resulted  in  the  control  of  a  large  percentage  of  the  first  brood  of  codling 
moth,  somewhat  better  results  ma}'  usually  be  expected  from  a  greater  num- 
ber of  applications.  Page  385 

4.  In  spraying  for  the  second  brood  of  codling  moth  in  1901,  Paris  green 
applied  without  lime  caused  excessive  dropping  of  the  fruit.  Page  393 

5.  Many   apples   from   the   sprayed   trees   were   slightly   blemished  by 
codling  moth  injuries  which  did  not  extend  much  below  the  surface.     Fruit 
so  injured  kept  well  in  cold  storage.  Page  397 

6.  Laboratory  experiments  showed  conclusively  that  it  is  possible  to  kill 
at  least  part  of   the  second  brood  larvae  of  the  codling  moth  by  means  of  a 
poisonous  spray  applied  even  after  the  worms  have  entered  the  fruit. 

Page  400 

7.  In  1902  double  strength  home-made  arsenate  of  lead  gave  better  re- 
sults against  the  second  brood  of  codling  moth  than  did  Paris  green  used 
with  lime.  Page  403 

8.  In  1903  spraying  for  the  second  brood  of  the  codling  moth  was  much 
less  effective  than  in  1902,  owing  probably  to  the  fact  that  a  much  larger 
proportion  of  ,  the   larvae  entered  the  apples  at  the  calyx.     Paris  green   in 
combination  with  Bordeaux  mixture  gave  better  results  than  any  of  the  other 
mixtures  tested,  though  the  double  strength  arsenate  of  lead  proved  nearly 
as  effective.  Page  408 

9.  Since  it  seemed  probable  that  the  failure  to  secure  more  marked  re- 
sults from  the  late  spra3ring  in  1903  was  due,  at  least  in  part,  to  a  lack  of 
thoroughness  in  the  early  spraying,  certain  trees  designed  for  the  test  of  late 
spraying  in  1904  were  selected  while  in  bloom,  and  thereafter  sprayed  under 
careful   supervision.     Heavy  sprajung  early   in   the  season    gave  decidedly 
better  results  than  light  spraying,   in  reference  to  the  control  of  the  second 
brood  of  the  codling  moth,  even  though  both  lots  of  trees  were  treated  alike 
in  the  late  sprayings.  Page  412 

10.  Marked  results  were  secured,  from  all  the  late  spraying  in  1904.     The 
double  strength  arsenate  of  lead  gave  the  best  results,  though  Paris  green  in 
combination  with  dilute  Bordeaux  mixture  resulted  in  the  saving  of  nearly 
as  much  fruit.  .  Page  415 

11.  The  average  results  for  three  years  in  the  test  of  different  spraying 
mixtures  for  the  second  brood  of  codling  moth  at  Urbana,  show  a  decided 
advp.ntage  in  favor  of  late  spraying  as  compared  with  no  late  spra3'irig.     Of 
the   different   mixtures   used   each  of  the  three  years,   the  double   strength 
arsenate  of  lead  gave  the  best  average  results,  though  for  the  two  years  in 
which  Paris  green  was  used  in  combination  with  standard  Bordeaux  mixture, 
this  material  gave  fully  as  good  average  results  as  the  arsenate  of  lead. 

Page  418 

12.  In  1906,  tests  in  spra3'ing  for  the  second  brood  of  codling  moth  were 
made  in  commercial  orchards  near  Quincy  and  Griggsville.     At  both  places 
the  attack  of  the  codling  moth  was  so  slight  that  even  the  check  trees  were 
not  badly  infested.  Page  419 

13.  Conclusions.  Page  427 


BY  JOHN  W.  LLOYD,  CHIEF  ASSISTANT  IN  HORTICULTURE 

Spraying  is  recognized  by  Illinois  apple  growers  as  one  of  the 
essential  operations  in  the  production  of  high  grade  fruit.  The 
accepted  practice  is  to  spray  the  orchard  three  times  each  year,  using 
the  combined  mixture  of  Bordeaux  and  Paris  green  or  some  other 
arsenical  poison.  The  usual  recommendation  is  to  make  the  first 
application  just  before  the  blossoms  open,  the  second  immediately 
after  the  petals  fall,  and  the  third  a  week  or  ten  days  later;  and 
the  best  orchardists  conform  as  closely  to  this  outline  as  the  weather 
conditions  and  the  size  of  the  orchard  as  compared  with  the  work- 
ing force  will  permit.  The  first  application  is  directed  primarily 
against  the  apple  scab,  but  Paris  green  is  included  in  the  mixture 
for  the  purpose  of  killing  any  canker  worms  or  other  leaf-eating 
insects  which  may  be  present  at  that  time.  The  second  application 
is  considered  the  most  important  one  in  reference  to  the  codling 
moth,  but  is  also  important  in  reference  to  the  scab.  The  third 
application  likewise  is  directed  against  both  these  enemies.  It  is  not 
a  common  practice  in  this  State  to  spray  for  the  codling  moth  alone, 
since  the  scab  is  very  prevalent  and  can  be  combated  at  the  same 
time.  Hence,  when  spraying  for  the  codling  moth,  the  combined 
mixture  of  Bordeaux  and  Paris  green  is  ordinarily  used. 

TIME  OF  APPLICATION 

To  be  most  effective  against  the  codling  moth,  the  application 
after  the  falling  of  the  petals  must  be  made  while  the  calyxes  of  the 
young  apples  are  still  open,  in  order  that  the  poison  may  become 
lodged  in  the  calyx  cavities  and  remain  there  in  readiness  for  the 
young  worms,  which  enter  after  the  calyxes  have  closed,  and  feed 
for  a  few  days  within  the  calyx  cavities  before  going  deep  into  the 
flesh.  It  is  ordinarily  considered  that  from  75  to  85  percent  of  the 
larvae  entering  the  apples  in  spring  gain  entrance  at  the  calyx  end ; 
and  observations  made  at  the  Illinois  Experiment  Station  in  1904 
correspond  very  closely  to  these  figures.  Careful  examinations  were 
made  of  all  the  apples  produced  by  three  unsprayed  Duchess  trees 
including  all  windfalls  which  dropped  after  the  "June  drop,"  and  all 

377 


378 


BULLETIN  No.  114. 


[  March, 


the  hand-picked  fruit.  Of  these  apples  1,065  had  been  injured  by 
the  first  brood  of  the  codling  moth ;  and  77.74  percent  of  the  injured 
apples  had  been  attacked  at  the  calyx.  Six  hundred  and  eighty- 
seven  (687)  windfalls  from  three  unsprayed  Whitney  trees  were 
also  found  to  be  injured  by  the  first  brood  of  the  codling  moth,  and 
79.91  percent  of  these  had  been  entered  at  the  calyx. 

The  fact  that  so  large  a  proportion  of  the  apples  attacked  by 
the  codling  moth  are  entered  by  way  of  the  calyx  emphasizes  the 
importance  of  getting  poison  into  the  calyx  cavities.  If  only  a  few 
trees  are  to  be  sprayed,  there  is  usually  little  difficulty  in  making 
the  application  before  the  calyxes  close,  but  if  the  orchard  is  large, 
or  the  working  force  and  equipment  inadequate,  or  the  weather  un- 
favorable, the  completion  of  this  application  may  be  so  delayed  that 
some  of  the  calyxes  close  before  the  poison  is  applied.  It  is  im- 
portant, therefore,  to  know  how  long  the  calyxes  are  likely  to  remain 
open,  in  order  that  sufficient  help  and  apparatus  may  be  employed  to 
get  over  the  orchard  in  ample  time. 

The  length  of  time  which  elapses  from  the  falling  of  the  petals 
until  the  calyxes  are  fully  closed  varies  for  different  varieties,  and 
doubtless  for  the  same  variety  in  different  seasons.  It  also  varies 
for  different  clusters  upon  the  same  tree.  In  1902,  twenty  clusters 
each  of  Whitney,  Duchess,  and  Fameuse  were  marked  with  tags,  and 
a  record  kept  regarding  the  date  of  opening  of  each  blossom,  the 
falling  of  the  petals  and  the  closing  of  the  calyxes.  From  this 
record,  the  number  of  days  from  the  falling  of  the  petals  of  the 
latest  flower  in  each  cluster  to  the  complete  closing  of  the  first  calyx 
in  the  cluster  was  determined.  The  shortest  time  was  eight  days 
and  the  longest  seventeen  days.  The  number  of  clusters  for  each 
number  of  days  is  indicated  in  the  following  table.  Since  not  all 
the  clusters  set  fruit,  the  total  number  is  in  each  case  less  than 
twenty. 

TABLE  1. — DAYS  FROM  PALLING  OF  PETALS  TO  CLOSING  OF  CALYXES  IN 

INDIVIDUAL  CLUSTERS 


No.  of  days. 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

Total. 

Whitney 

2 

4 

1 

4 

3 

1 

15 

Duchess 

1 

3 

4 

4 

1 

2 

2 

17 

Fameuse 

2 

4 

3 

0 

2 

2 

15 

1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


379 


Observations  were  also  made  regarding  the  behavior  of  entire 
trees  of  nine  different  varieties.  The  figures  given  below  indicate 
the  number  of  days  from  the  time  when  nearly  all  the  petals  had 
fallen — that  is,  the  earliest  date  after  blossoming  that  spraying 
might  be  commenced — until  the  first  calyxes  were  fully  closed. 


Dominie    7 

Duchess    7 

Minkler    7 

Whitney 8 

Winesap    9 


Grimes    10 

Ben  Davis  n 

Fameuse    1 1 

Willow  Twig  ii 


PIG.  1     THE  CALYXES  OF  BLOSSOMS  WHICH  FAIL  TO  SET  FRUIT 
SEEM  NEVER  TO  CLOSE. 


380 


BULLETIN  No.  114. 


[March, 


Nearly  all  the  calyxes  were  closed  on  the  respective  trees  in 
from  four  to  five  days  after  the  closing  of  the  first  calyxes.  This 
refers  only  to  the  calyxes  of  apples  which  were  developing  nor- 
mally, and  not  to  abortive  specimens.  The  calyxes  of  blossoms 
which  fail  to  set  fruit  seem  never  to  close  even  though  the  rudi- 
mentary fruits  may  persist  on  the  tree  until  after  the  other  calyxes 
are  closed.  (See  Fig.  i.) 

Although  several  fruits  may  set  in  a  cluster,  many  varieties  nor- 
mally mature  only  one  fruit  to  each  cluster.  The  others  usually 
drop  off  while  quite  small.  The  fruit  which  usually  has  the  best 
chance  of  surviving  in  the  struggle  among  the  individuals  of  a 
cluster  is  the  one  which  develops  from  the  blossom  which  opens  first. 
This  is  usually  the  central  blossom  of  the  cluster  and  therefore  has 
an  advantage  in  location  with  reference  to  the  food  supply  as  well 
as  an  advantage  in  point  of  time. 

Observations  made  on  thirty  clusters  each  of  Whitney,  Duchess, 
and  Fameuse  in  the  spring  of  1902,  when  the  season  was  normal 
and  the  conditions  therefore  favorable  for  the  normal  development 
of  the  flowers,  show  that  the  length  of  time  which  elapsed  between 
the  opening  of  the  first  and  second  blossoms  in  a  cluster  varied  from 
one  to  three  days,  as  is  indicated  in  the  table  below. 

TABLE  2. — DAYS  FROM  FIRST  TO  SECOND  BLOSSOM  IN  SAME  CLUSTER,  1902 


Number  of  days. 

1 

2 

3 

Total. 

Number  of  clusters,    "Whitney 

19 

5 

6 

30 

"            "           Duchess 

3 

26 

1 

30 

"        "            "          Pameuse 

3 

27 

30 

In  1903,  fifteen  clusters  each  of  Whitney,  Duchess,  Ben  Davis, 
and  Grimes  were  marked  for  observation.  The  weather  during  the 
blossoming  season  was  abnormal,  there  being  two  short  periods  of 
warm,  bright  weather,  each  followed  by  a  cool  period  including  a 
frost.  In  some  of  the  clusters  of  Whitney  and  Duchess  the  first 
blossom  opened  at  the  very  end  of  the  first  warm  period,  and  the 
cool  period  immediately  following  retarded  the  development  of  the 
later  flowers.  None  of  the  Grimes  or  Ben  Davis  opened  during 
the  first  warm  period.  The  first  blossom  in  nearly  every  cluster  of 
Grimes  opened  during  the  cool  period,  and  the  other  flowers  ap- 
peared at  the  beginning  of  the  second  warm  period.  None  of  the 
Ben  Davis  opened  until  the  approach  of  the  second  warm  period; 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


381 


then  they  developed  rapidly,  so  that  in  most  cases  the  second  blos- 
som appeared  within  a  day  after  the  first.  The  following  table 
shows  the  range  of  time  for  each  variety  and  the  number  of  clusters 
for  each  number  of  days. 

TABLE  3.— DAYS  FROM  FIRST  TO  SECOND  BLOSSOM  IN  SAME  CLUSTER,  1903 


Number  of  days. 

Less 
than  1 

1 

2 

3 

4 

Total. 

Number  of  clusters,  Whitney 

2 

4 

3 

3 

2 

14* 

"          "        Duchess 

1 

2 

2 

3 

7 

15 

"          "           Grimes 

3 

11 

1 

15 

11        "          "     Ben  Davis 

4 

8 

2 

1 

15 

These  observations  show  that  the  first  blossom  in  a  cluster  may 
open  from  a  few  hours  to  three  or  four  days  ahead  of  any  of  the 
other  blossoms.  This  relative  forwardness,  especially  if  marked,  is 
usually  maintained,  so  that  the  earliest  blossom  to  open  loses  its 
petals  first,  and  the  calyx  of  the  young  apple  developing  from  it 
closes  before  those  of  the  other  apples  in  the  cluster.  (See  Fig.  2.) 

If  then,  the  earliest  apple  in  each  cluster — and  the  one  of  which 
the  calyx  closes  first — is  most  likely  to  persist  and  mature,  it  is 
highly  important  that  the  spraying  be  timed  with  reference  to  the  de- 
velopment of  these  most  advanced  specimens  rather  than  to  the 
average  development  of  the  entire  setting  of  fruit,  or  the  belated 
specimens. 

Taking  into  consideration  the  variation  in  the  different  clusters 
on  the  same  tree,  and  the  fact  that  the  calyx  cavities  can  be  more 
readily  reached  by  the  spray  if  the  calyx  is  entirely  open  rather  than 
partially  closed,  it  is  probable  that  the  entire  orchard  should  be 
sprayed  within  seven  days  from  the  time  that  most  of  the  petals 
have  fallen ;  and  sufficient  force  and  apparatus  should  be  available  to 
accomplish  this  end  even  if  delays  are  encountered  by  reason  of 
rainy  weather  or  unavoidable  accidents.  It  is  true  that  for  some 
varieties  a  longer  time  might  be  allowed,  and  that  in  a  mixed  or- 
chard spraying  could  be  commenced  upon  the  earlier  blossoming 
varieties  before  the  others  were  ready,  and  thus  the  time  for  the 
entire  orchard  extended.  Nevertheless,  seven  days  is  a  safe  basis 


*One  cluster  was  accidentally  broken  off  before  the  second  blossom  opened. 


382 


BULLETIN  No.  114. 


upon  which  to  calculate  the  amount  of  working  force  and  appara- 
tus needed. 

METHOD  OF  APPLICATION 

The  method  of  applying  the  material  may  have  as  important  a 
bearing  upon  the  results  as  has  the  time  of  application.  As  already 
mentioned,  the  prime  object  of  the  application  just  after  the  falling 
of  the  petals  is  to  place  the  poison  within  the  calyx  cavities  of  the 
young  apples.  If  it  were  possible  to  place  a  quantity  of  poison 


FIG.  2.    THE  CALYXES  OF  THE  DIFFERENT  APPLES  IN  THE  SAME  CLUSTER 
DO  NOT  CLOSE  AT  THE  SAME  TIME. 


1901.'}  SPRAYING  FOR  THE  CODLING  MOTH.  383 

within  the  calyx  cavity  of  each  and  every  apple  upon  the  tree,  very 
few  codling  moth  larvae  attempting  to  enter  by  way  of  the  calyx 
would  survive. 

Although  in  commercial  spraying  it  is  practically  impossible  to 
attain  this  ideal,  nevertheless  some  methods  of  application  more 
closely  approximate  it  than  do  others.  In  the  spring  of  1902  vari- 
ous tests  were  made  to  determine,  if  possible,  the  most  efficient 
method  of  making  the  application.  In  all  the  tests  the  same  pump 
was  used,  but  it  was  worked  at  different  pressures  and  with  differ- 
ent nozzles,  and  different  amounts  of  material  were  applied.  A 
small  portion  of  a  tree  was  treated  according  to  each  method.  As 
soon  as  the  material  was  dry,  notes  were  made  regarding  the  amount 
and  distribution  of  the  spraying  material  visible  about  the  calyxes. 
In  all  cases  the  combined  mixture  of  Bordeaux  and  Paris  green 
was  used.  The  methods  and  results  were  as  follows : 

1.  Double  Vermorel  nozzle  with  fine  caps : 

a.  High  pressure;*    spraying   stopped  before   fine   drops   ran   together. 

Only  a  small  amount  of  material  visible,  many  apples  showing  none 
whatever. 

b.  High  pressure;   spraying  continued  until  after  drops  had  run  together. 

Calyx  cavities  well  filled  with  material. 

c.  Low  pressure;    spraying  stopped  before   drops   ran   together.     Few 

calyxes  hit;    unsatisfactory.' 

d.  Low  pressure;    spraying  continued  for  some  time.     Most  of  calyxes 

hit,  but  not  properly  covered. 

2.  Double  Vermorel  nozzle  with  coarse  caps : 

a.  High  pressure;    spraying  stopped  before   drops   ran   together.     Not 

much  material  visible. 

b.  High  pressure;    spraying  continued  until  after  drops   ran   together. 

Most  of  calyx  cavities  filled  with  the  material. 

c.  Low  pressure,  using  small  amount  of  material.     Not  enough  material, 

and  distribution  poor;   unsatisfactory. 

d.  Low  pressure;   spraying  continued  for  some  time.    Distribution  poor ; 

unsatisfactory. 
3.  Bordeaux  nozzle : 

a.  High   pressure;     spraying   stopped   very   soon.      Not   much   material 

remained  on  the  apples ;    distribution  poor. 

b.  High  pressure;   spraying  continued  for  some  time.    Distribution  poor. 

The  application  which  was  most  effective  in  filling  the  calyx 
cavities  was  that  made  in  the  form  of  a  fine  mist  by  means  of  a 
Vermorel  nozzle  under  high  pressure,  and  continued  until  the  fine 
drops  gathering  in  the  calyx  cavity  ran  together  in  the  form  of  one 
or  a  few  large  drops.  If  sufficient  pressure  was  kept  up  to  make 


*No  pressure  gauge  was  used,  but  the  "high  pressure"  was  probably  about 
eighty  pounds  and  the  "low  pressure"  about  thirty-five  pounds. 


384 


BULLETIN  No.  114. 


[March, 


the  spray  very  fine,  the  coarse  caps  gave  as  good  results  as  the  fine 
caps,  but  this  was  difficult  to  accomplish  with  a  hand  pump.  It 
seemed  to  make  little  difference  whether  the  nozzle  was  held  close 
to  the  apples  or  at  a  distance  of  two  or  three  feet,  since  the  spray 
leaves  the  nozzle  in  the  form  of  a  mist. 

To  further  determine  the  distribution  of  spraying  material  ap- 
plied in  different  ways,  one  hundred  apples  were  picked  at  random, 
June  26,  from  each  of  two  Whitney  trees  which  had  received  one 
application  of  spraying  material  May  8.  Both  were  sprayed  with 
fine  Vermorel  nozzles,  under  high  pressure,  but  one  was  sprayed 
until  the  drops  of  material  ran  together  and  the  tree  was  dripping, 
while  in  the  other  case  care  was  taken  to  stop  spraying  before  the 
fine  drops  ran  together.  Each  apple  was  cut  open  with  a  sharp 
knife  and  the  calyx  cavity  carefully  examined  under  a  lens  in  search 
of  particles  of  spraying  material.  It  was  observed  that  in  some 
cases  the  material  had  penetrated  into  the  calyx  cavity  beyond  the 
point  of  attachment  of  the  stamens,  while  in  other  cases  it  had  not. 
The  results  of  the  examination  were  as  follows : 

TABLE  4.— DISTRIBUTION  OF  MATERIAL  IN  HEAVY  AND  LIGHT  SPRAYING 


Heavy 

spray. 

Light 
spray. 

Specimens    in     which     spraying     material    was 
visible  in  calyx  cavity  

86 

20 

Spraying  material  beyond  stamens  

67 

8 

Spraying"  material  not  beyond  stamens  

19 

12 

Specimens  in  which  no  spraying  material  was 
visible  in  catyx  cavity  

14 

80 

Number  of  specimens  examined  

100 

100 

That  the  method  of  application  which  left  the  spraying  material 
deposited  in  the  calyx  cavities  of  the  greater  proportion  of  the  ap- 
ples was  of  greater  efficiency  than  the  other  in  controlling  the 
codling  moth  is  shown  by  the  fact  that  ninety-seven  of  the  hundred 
apples  from  the  heavily  sprayed  tree  were  perfectly  free  from  worm 
injury,  and  that  only  two  worms  had  gained  entrance  by  way  of 
the  calyx,  while  in  the  hundred  apples  from  the  lightly  sprayed  tree 
thirteen  live  worms  were  found,  ten  of  which  had  entered  through 
the  calyx.  One  other  worm  had  also  entered  by  way  of  the  calyx, 
but  was  not  found.  The  test  was  repeated  in  1904.  Two  Whitney 
trees  were  sprayed  May  18 ;  one  heavily  and  the  other  lightly.  One 
hundred  apples  picked  at  random  from  each  were  examined  June  30. 
Nine  of  the  hundred  apples  from  the  lightly  sprayed  tree  showed 
evidences  of  codling  moth  attacks,  though  only  two  worms  (one 


1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  385 

living  and  one  dead)  were  found  in  the  calyx  cavities.  Refuse  left 
by  the  other  seven  worms  was  found  in  the  calyx  cavities,  but  the 
worms  themselves  were  lacking.  It  is  probable  that  they  died  as  a 
result  of  eating  poison,  but  did  not  consume  sufficiently  large  quan- 
tities to  kill  them  immediately.  Hence  they  were  able  to  feed  in 
the  calyx  cavity  sufficiently  long  to  leave  considerable  refuse*. 
On  the  other  hand,  in  only  one  apple  of  the  hundred  from  the  heav- 
ily sprayed  tree  was  there  any  evidence  of  the  visit  of  a  worm,  and 
that  worm  did  not  proceed  beyond  the  calyx  cavity.  If  other  worms 
attacked  these  apples,  they  were  evidently  killed  before  they  did 
sufficient  feeding  to  leave  any  traces  of  their  work. 

NUMBER  OF  APPLICATIONS 

In  the  foregoing  discussion  regarding  methods  of  application, 
reference  has  been  had  merely  to  the  application  immediately  fol- 
lowing the  falling  of  the  petals.  Experiments  were  also  under- 
taken to  determine  the  relative  efficiency  of  different  numbers  of 
applications  made  in  different  ways.  In  the  spring  of  1902,  eleven 
Whitney  trees  which  had  already  received  .the  usual  application  of 
Bordeaux  mixture  and  Paris  green  before  blossoming,  were  selected 
for  the  purpose  of  making  this  test.  The  various  trees  were  sprayed 
as  indicated  in  the  outline  below.  In  all  cases  the  combined  mixture 
of  Bordeaux  and  Paris  green  was  used,  and  was  applied  by  means 
of  a  barrel  pump  carrying  one  lead  of  hose,  equipped  with  a  bamboo 
extension  rod  and  a  double  Vermorel  nozzle  fitted  with  fine  caps. 
The  "high  pressure"  used  was  about  eighty  pounds  and  the  "low 
pressure"  about  thirty-five  pounds.  Under  the  high  pressure  the 
spray  issued  with  considerable  force  and  in  the  form  of  very  fine 
mist-like  drops,  while  under  the  low  pressure  the  drops  were  much 
larger  and  the  discharge  weak.  In  making  a  "heavy  application," 
the  spraying  was  continued  until  the  fine  drops  ran  together  and 
the  material  began  to  drip  from  the  trees.  In  making  a  "light  ap- 
plication," the  spraying  was  stopped  before  the  fine  drops  ran  to- 
gether. In  both  cases,  the  attempt  was  made  to  secure  a  uniform 
distribution  of  the  material  over  the  entire  tree.  In  making  a  "care- 
less application,"  low  pressure  and  a  small  amount  of  material  were 


*It  is  true  that  there  is  no  positive  proof  that  these  worms  were  killed  by 
eating  poison,  for  further  observations  made  in  this  connection  show  that  apples 
from  unsprayed  trees  may  sometimes  contain  similar  evidences  of  worms  having 
ceased  operations  early  in  their  career. 


386 


BULLETIN  No.  114. 


[March, 


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which  entered 
f  worms  enter- 
not  injured  

pies  apparently  not  attacked.  .  . 
.acked  by  codling  moth  at  calyx  : 
Live  worm  in  calyx  cavity  
Dead  worm  in  calyx  cavity  
Worm  stopped  in  cavity,  but  no 
Worm  not  stopped  in  cavity 
Live  worm  in  apple  
Worm  not  found  
.acked  by  codling  moth  at  other 
Worm  reached  interior  of  fruit 
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al  number  of  live  worms  found 
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ing  at  calyx  " 
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1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  387 

used ;  and  no  particular  care  was  taken  to  reach  all  parts  of  the  tree. 
The  various  treatments  were  as  follows : 

1.  Check.     Not  sprayed  (except  before  blossoming). 

2.  One  heavy  application;    high  pressure;    May  8. 

3.  One  light  application;    high  pressure;    May  8. 

4.  One  careless  application ;    low  pressure ;    May  8. 

5.  Two  heavy  applications ;   high  pressure ;    May  8,  and  16. 

6.  Check.     Not  sprayed  (except  before  blossoming). 

7.  Two  light  applications;   high  pressure;   May  8,  and  16. 

8.  Two  careless  applications ;    low  pressure ;    May  8,  and  16. 

9.  Three  heavy  applications ;   high  pressure ;   May  8,  16,  and  22. 

10.  Two  heavy  applications  followed  by  two  light  applications;    all  under 

high  pressure;   May  8,  16,  23,  and  June  5. 

11.  Check.    Not  sprayed  (except  before  blossoming). 

June  26,  one  hundred  apples  were  picked  without  selection  from 
each  of  these  trees,  and  carefully  examined  for  codling  moth  in- 
juries. Each  apple  was  cut  open  so  that  its  exact  condition  could 
be  determined.  *  The  results  of  this  examination  are  given  in  Table  5 . 

Apples  in  which  worms  had  been  stopped  in  the  calyx  cavity 
were  counted  as  not  injured ;  those  in  which  live  worms  were  found 
in  the  calyx  cavity,  or  in  which  worms  had  proceeded  to  the  interior 
(whether  found  or  not),  were  counted  as  injured.  It  is  perfectly 
evident  that  the  heavy  spraying  was  more  effective  than  the  light 
or  careless  spraying,  and  there  seemed  to  be  a  slight  advantage  in 
favor  of  more  than  one  application.  The  heavy  spraying  seemed 
to  be  more  effective  than  the  other  methods  against  the  worms  at- 
tacking the  sides  of  the  fruit  as  well  as  against  those  seeking  en- 
trance at  the  calyx. 

July  2,  the  ground  under  the  trees  in  this  experiment  was  cleared 
of  all  windfalls,  so  that  from  that  date  an  accurate  record  could  be 
kept  of  all  apples  which  fell.  The  fallen  apples  were  gathered  at 
frequent  intervals  from  July  8  to  29  and  the  number  from  each  tree 
recorded.  Each  apple  was  cut  open  and  a  record  made  regarding 
the  number  injured  by  the  codling  moth.  On  July  29,  the  apples 
remaining  on  the  trees  were  harvested,  sorted  and  counted.  Those 
showing  any  indication  of  worm  injury  were  cut  open  and  .critically 
examined.  The  second  brood  larvae  of  the  codling  moth  were  en- 
tering the  apples  at  this  time,  but  their  work  could  readily  be  dis- 
tinguished from  that  of  the  first  brood,  and  only  the  first  brood 
injuries  are  to  be  considered  in  this  connection.  The  results  of 
these  counts  and  examinations  are  given  in  Table  6.  The  windfalls 
include  only  those  which  dropped  after  July  2 ;  the  "total  crop"  in- 


*The  apples  from  trees  2  and  3  are  those  previously  mentioned  as  having 
been  examined  to  determine  the  distribution  of  the  spraying  material. 


388 


BULLETIN  No.  114. 


[March, 


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1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  389 

eludes  the  fruit  picked  from  the  trees  July  29  and  all  windfalls  which 
dropped  after  July  2.  The  term  "wormy,"  or  "worm-injured" 
means  injured  by  a  first  brood  larva  of  the  codling  moth. 

By  comparison  of  the  figures  for  sprayed  and  unsprayed  trees 
it  can  readily  be  seen  that  all  the  spraying  was  of  benefit,  even  the 
careless  applications  resulting  in  the  saving  of  considerable  fruit. 
One  heavy  application  gave  much  better  results  than  one  light  appli- 
cation. The  fact  that  the  tree  which  received  two  heavy  applica- 
tions produced  a  greater  percentage  of  wormy  fruits  than  the  one 
which  received  only  one  heavy  application  can  be  partially  accounted 
for  by  the  fact  that  this  tree  bore  a  much  smaller  number  of  fruits, 
for  it  is  generally  conceded  that  the  smaller  the  crop  the  higher  the 
percentage  of  wormy  fruit  is  likely  to  be.  It  is  also  true  that  even 
when  the  number  or  fruits  borne  by  each  of  several  trees  is  nearly 
the  same,  one  tree  may  be  more  severely  attacked  than  another.  This 
is  illustrated  by  the  differences  in  the  percentages  of  wormy  fruit 
from  the  three  unsprayed  trees,  even  though  they  were  of  the  same 
variety  in  the  same  orchard  and  within  a  few  rods  of  one  another. 
If  the  percentage  of  the  total  crop  which  remained  on  the  tree  unin- 
jured by  the  first  brood  of  codling  moth  until  picked  be  taken  as 
the  basis  of  comparison,  the  tree  which  received  two  heavy  appli- 
cations is  slightly  ahead  of  the  one  which  received  only  one  appli- 
cation. This  is  due  to  the  fact  that  a  smaller  percentage  of  the 
fruits  fell  before  they  were  ripe.  The  two  treatments  which  stand 
out  clearly  ahead  of  the  others  in  reducing  the  percentage  of  wormy 
fruits,  and  in  maturing  a  higher  percentage  of  the  total  crop  are 
those  given  trees  No.  9  and  10;  namely:  three  heavy  applications, 
and  two  heavy  followed  by  two  light  applications. 

This  experiment  regarding  the  different  methods  of  spraying 
and  number  of  applications  was  repeated  in  1904.  However,  the 
spray  pump  was  fitted  with  a  pressure  gauge  so  that  the  exact  pres- 
sure could  be  known.  The  variety  used  this  time  was  the  Duchess. 
The  trees  were  selected  while  in  bloom,  and  had  been  sprayed  once 
before  blossoming.  That  application  is  not  considered  in  this  ex- 
periment, since  it  has  no  direct  bearing  upon  the  control  of  the 
codling  moth.  The  first  application  after  the  petals  had  fallen  was 
made  May  21,  the  "high  pressure"  spraying  upon  this  date  being 
done  with  a  gasoline  power  sprayer  at  a  pressure  of  125  pounds.  The 
"low  pressure"  spraying  was  done  with  a  hand  pump  at  a  pressure 
of  32^  to  371/2  pounds,  there  being  a  variation  of  five  pounds  be- 
tween the  beginning  and  end  of  each  stroke.  The  second  applica- 
tion was  made  May  27,  the  high  pressure  spraying  being  done  with 


390 


BULLETIN  No.  114. 


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1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  391 

a  hand  pump  at  a  pressure  of  80  to  100  pounds,  for  at  this  pressure 
there  was  a  range  of  twenty  pounds  at  every  stroke.  The  low  pres- 
sure used  at  this  date  was  the  same  as  for  the  first  application.  The 
third  application  was  made  June  6,  with  a  gasoline  power  sprayer 
operated  at  a  pressure  of  125  pounds,  and  the  fourth  application, 
June  13,  with  a  hand  pump  at  a  pressure  of  80  to  100  pounds.  All 
applications  were  made  later  than  in  1902  on  account  of  the  season 
being  later. 

On  June  27,  all  windfalls  of  every  description  were  gathered 
from  under  each  of  the  trees.  All  except  the  very  small,  shriveled 
specimens  which  had  dropped  very  early,  were  counted  and  exam- 
ined for  codling  moth  injuries.  From  that  date  until  July  28,  the 
windfalls  were  gathered  every  few  days,  and  a  record  kept  regarding 
the  number  from  each  tree.  These  windfalls  were  cut  open  and 
examined  for  codling  moth  injuries,  and  a  record  kept  regarding 
the  condition  of  those  from  each  tree. 

On  July  28,  the  apples  remaining  on  the  trees  were  picked, 
counted  and  carefully  sorted.  All  fruits  showing  any  indication  of 
having  been  attacked  by  the  codling  moth  were  cut  open  to  deter- 
mine the  exact  nature  and  extent  of  the  injury. 

The  results  of  the  above  mentioned  counts  and  examinations 
are  given  in  Table  7. 

It  will  be  seen  that  again  all  the  methods  of  spraying  employed 
resulted  in  a  diminution  of  the  percentage  of  the  crop  injured  by 
the  codling  moth.  However,  the  results  appear  less  markedly  in 
favor  of  the  greater  number  of  applications,  or  of  one  heavy  as 
compared  with  one  light  application,  than  was  the  case  in  1902.  In 
fact,  the  tree  which  was  given  only  one  "careless"  application  had  a 
smaller  percentage  of  the  total  crop  injured  by  worms  than  any 
other  tree  except  the  one  receiving  three  heavy  applications ;  and  it 
also  had  the  largest  percentage  of  the  total  crop  remaining  on  the 
tree  uninjured  until  mature.  It  must  be  mentioned  in  this  connec- 
tion that  this  so-called  "careless"  application  was  probably  made  in 
a  more  thorough  manner  than  many  orchardists  usually  spray,  and 
it  is  also  possible  that  this  tree  may  not  have  been  so  severely  at- 
tacked by  the  codling  moth  as  some  others  in  the  experiment. 

Another  difference  in  the  results  as  compared  with  those  of  1902 
was  that  a  much  larger  percentage  of  the  crop  dropped  before  ripen- 
ing. This  can  be  partially  accounted  for  by  the  fact  that  windfalls 
dropping  somewhat  earlier  were  included  in  the  count,  and  that  the 
Duchess  in  this  locality  usually  drops  worse  than  the  Whitney. 
However,  the  fact  that  the  smallest  percentage  of  fallen  fruit  was 


392  BULLETIN  No.  114.  [March, 

from  the  tree  receiving  one  "careless"  application,  and  the  next 
smallest  percentage  from  the  tree  receiving  two  such  applications 
challenges  explanation.  This  may  possibly  have  been  due  partly 
to  individual  differences  in  the  respective  trees  or  to  local  conditions 
affecting  them.  That  such  differences  may  occur  is  illustrated  by 
the  fact  that  one  of  the  unsprayed  trees  lost  a  much  larger  propor- 
tion of  its  crop  by  dropping  than  did  the  other  two.  Yet  it  is  prob- 
able that  another  factor  had  a  more  important  influence.  The 
foliage  as  well  as  the  fruit  dropped  badly  from  the  heavily  sprayed 
trees,  and  much  of  the  fruit  was  russeted  by  the  spray.  The  lightly 
sprayed  trees  did  not  lose  much  foliage,  but  some  of  the  fruit  was 
russeted,  though  not  so  badly  as  that  from  the  heavily  sprayed  trees 
The  carelessly  sprayed  trees  showed  very  little  russet  on  the  fruit 
and  practically  no  dropping  of  the  foliage.  There  seemed  to  be  a 
fairly  constant  relation  between  the  amount  of  spraying  material 
applied  and  the  russeting  of  fruit  and  dropping  of  foliage.  It  is 
possible  that  if  more  lime  had  been  used  these  injuries  would  not 
have  followed.  However,  the  whole  question  of  russeting  of  fruit 
and  injury  to  foliage  is  not  thoroughly  understood  and  is  now  the 
object  of  a  special  investigation  by  the  department. 

It  seems  then  that  the  results  of  the  work  in  1904  do  not  war- 
rant the  drawing  of  definite  conclusions  regarding  the  best  method 
and  number  of  applications  of  spraying  material  for  controlling  the 
first  brood  of  the  codling  moth.  However,  taking  into  considera- 
tion both  seasons'  work,  it  appears  evident  that  the  application  made 
just  after  the  falling  of  the  petals  should  be  sufficiently  heavy  and 
applied  with  sufficient  force  to  place  considerable  spraying  material 
within  the  calyx  cavities  of  the  young  apples.  It  is  probable  that  at 
least  one  other  application  should  be  made,  and  the  results  in  1902 
show  a  marked  advantage  in  favor  of  three  or  even  four  applica- 
tions. Whether  these  subsequent  applications  should  be  heavy  or 
light,  does  not  appear  from  these  investigations.  It  is  thought  by 
some  that  the  later  applications  should  be  rather  light  with  a  view 
to  securing  a  uniform  distribution  of  the  spraying  material  over  the 
sides  of  the  young  apples,  for  the  purpose  of  poisoning  the  worms 
seeking  to  enter  at  points  other  than  the  calyx. 


1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  393 


SPRAYING  FOR  THE1SECON1)  BROOD 

While  spraying  for  the  first  brood  of  the  codling  moth  is  a  com- 
mon practice  among  Illinois  apple  growers,  very  few  have  as  yet 
attempted  to  control  the  second  brood  by  spraying,  and  serious  dam- 
age often  results  from  the  work  of  this  late  brood  even  in  orchards 
which  have  been  sprayed  for  the  first  brood.  In  central  Illinois  the 
first  worms  of  the  second  brood  enter  the  apples  about  July  20,  and 
most  of  the  codling  moth  injuries  apparent  upon  winter  apples  at 
picking  time  are  due  to  the  work  of  this  brood.  A  serious  attack 
of  the  second  brood  is  most  disheartening  to  the  grower,  for  the 


FIG    3.    APPLES  RUINED  BY  SECOND  BROOD  LARVAE  OF  THE  CODLING  MOTH. 

injury  is  done  after  the  apples  have  attained  considerable  size  and 
even  commenced  to  color,  so  that  after  the  crop  is  apparently  made, 
a  large  percentage  of  it  may  be  ruined  by  the  worms. 

INVESTIGATIONS  IN  1901 

In  the  summer  of  1901,  tests  were  made  by  the  Illinois  Experi- 
ment Station  to  determine  the  feasibility  of  attempting  to  control 
the  second  brood  of  the  codling  moth  by  means  of  a  poisonous 
spray.  August  3,  after  the  larvae  were  entering  the  apples  in  large 
numbers,  five  trees,  one  each  of  Grimes,  Ben  Davis,  Winesap,  Fam- 
euse,  and  Longfield,  were  sprayed  with  Paris  green  used  at  the  rate 
of  one-fourth  pound  to  50  gallons  of  water.  Five  other  trees  of  the 
same  varieties  were  selected  and  left  unsprayed  as  checks.  All 
these  trees  had  received  the  three  usual  applications  of  Bordeaux 
mixture  and  Paris  green  in  the  spring.  August  10,  another  appli- 
cation of  Paris  green  was  made  to  the  trees  sprayed  August  3. 


394 


BULLETIN  No.  114. 


[March, 


Beginning  in  the  evening  of  August  17,  there  were  frequent 
showers  during  four  or  five  days.  The  sprayed  trees  seemed  to  be 
in  normal  condition  August  19,  but  on  August  23,  it  was  discovered 
that  the  foliage  of  all  the  sprayed  trees  was  badly  injured  and  that 
the  fruit  was  falling  much  worse  than  before  the  rains.  The  foliage 
injury  was  least  on  the  Grimes.  Although  the  falling  of  the  fruit 
may  have  been  due  partly  to  a  check  in  the  normal  activities  of  the 
tree  caused  by  the  injury  to  the  foliage,  it  was  evidently  due  pri- 
marily to  injury  to  the  stems  of  the  apples  themselves.  The  injury 
was  often  greatest  at  the  point  of  attachment  of  the  stem  and  apple 
— both  apple  and  stem  being  injured.  In  some  cases  the  skin  of 
the  entire  cavity  of  the  apple  had  turned  brown  and  the  flesh  was 
beginning  to  decay;  and  in  some  cases  the  entire  stem  had  turned 
brown  and  was  apparently  dead.  Many  apples  apparently  unin- 
jured hung  so  loosely  upon  the  tree  that  they  would  fall  if  jarred  or 
slightly  brushed  against.  This  was  especially  noticeable  in  the  case 
of  the  Winesap.  The  Grimes  and  the  Fameuse  were  much  less 
injured  in  the  flesh  about  the  stem  than  were  the  other  varieties. 

The  increase  in  the  amount  of  windfalls  from  the  sprayed  trees 
as  compared  with  unsprayed  trees  immediately  following  the  rains 
is  shown  by  the  following  table  giving  a  record  of  the  amount  (in 
pecks)  of  fallen  apples  gathered  from  under  each  tree  on  certain 
dates  preceding  and  following  the  injury. 

TABLE  8.— WINDFALLS  BEFORE  AND  AFTER  INJURY  TO  STEMS 


Grimes. 

Winesap. 

Ben  Davis. 

Long-field. 

Fameuse. 

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Before  the  injury  to  the  stems  occurred  nearly  all  the  windfalls 
consisted  of  apples  which  had  been  injured  by  worms.  After  the 
injury  to  the  stems,  a  large  percentage  of  the  apples  which  fell  from 
the  sprayed  trees  were  free  from  insect  attack.  The  windfalls  of 
three  varieties  gathered  on  five  different  dates  were  examined,  and 
the  percentage  of  sound  (t.  e.,  uninjured  by  worms)  fruit  deter- 
mined. The  percentages  are  given  in  the  following  table : 


1907.} 


SPRAYING  FOR  THE  CODLING  MOTH. 


395 


TABLE   9.— PERCENTAGES   OF   SOUND   WINDFALLS  BEFORE  AND  AFTER 

STEM  INJURY 


Date. 

Grimes. 

Wiuesap. 

Ben  Davis. 

Average. 

•d 
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August  16  

1.69 
0.0 

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0 
0 
0 

23.07 
6.66 
14.86 

7.89 
0.0 
3.94 

1.78 
0.0 
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0. 
0. 

5.53 

1.31 

"      19  

Average  before  injury 

August  23 

41. 
32. 
18. 
30.33 

0 
0 
0 
0 

92. 
92. 
86. 
90. 

4. 
0. 
0. 
1.33 

24. 
52. 

68. 

48. 

0. 
4.54 
1.96 
2.16 

56.11 

1.16 

"      26  

"      31  

Average  after  injury.  . 

In  spite  of  this  excessive  dropping  of  the  fruit  from  the  sprayed 
trees  for  a  few  days  following  the  rain,  the  total  percentage  of  the 
crop  on  the  trees  August  15  which  fell  before  the  harvest  averaged 
greater  for  the  unsprayed  than  for  the  sprayed  trees.  The  percent- 
ages for  each  variety  are  given  in  the  following  table : 

TABLE  10.— PERCENTAGE  OF  CROP  WHICH  FELL  BEFORE  THE  HARVEST 


Sprayed. 

Check. 

Grimes  

62.6 

92.5 

W  inesap  

70.9 

74.3 

Ben  Davis  

70.3 

63.5 

Longfield  

97.6 

96.9 

Fameuse  

87.7 

90.7 

Average  

77.82 

83.58 

This  means  that  the  spray  saved  more  apples  from  insect  injury 
than  it  caused  to  drop  by  reason  of  injury  to  the  stems. 

The  fruit  from  the  trees  in  this  experiment  was  picked  from 
September  23  to  September  28.  In  all  cases,  both  trees  of  the  same 
variety  were  picked  the  same  day.  The  fruit  was  carefully  sorted 
and  examined  for  codling  moth  injuries.  Many  of  the  fruits  which 
had  been  attacked  by  second  brood  larvae  of  the  codling  moth  were 
only  slightly  injured,  the  worm  having  ceased  operations  and  dis- 
appeared without  going  much  below  the  surface  of  the  fruit.  Such 
injuries  had  usually  partially  healed  over,  and  did  not  sufficiently 
blemish  the  fruit  to  render  it  unfit  for  market  or  even  for  storage. 
It  would  readily  be  classed  as  No.  2  under  the  most  rigid  grading. 

Since  nearly  all  the  fruit  had  fallen  from  the  Longfield  trees 
before  picking  time,  the  hand-picked  crop  of  this  variety  was  not 


396 


BULLETIN  No.  114. 


[March, 


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1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  397 

examined  for  worm  injuries.  The  results  of  the  examination  of  the 
four  other  varieties,  reduced  to  percentages,  are  given  in  Table  n. 
Tables  n  and  12  show  that  with  the  exception  of  one  variety  (the 
Fameuse)  a  smaller  percentage  of  the  apples  from  the  sprayed  trees 
were  visibly  attacked  by  worms  than  from  the  unsprayed  trees,  and 
that  the  average  percentage  for  the  four  varieties  (including  the 
Fameuse)  was  smaller  for  the  sprayed  than  for  the  unsprayed  trees. 
The  tables  further  show  that  a  very  much  larger  percentage  of  the 
worms  attacking  the  apples  had  stopped  before  going  to  the  interior 
in  the  case  of  fruits  from  the  sprayed  trees. 

STORAGE  TEST  OF  APPLES  ATTACKED  BY  CODLING  MOTH 

The  statement  has  been  made  that  fruits  attacked  by  second 
brood  larvae  of  the  codling  moth  in  which  the  worms  did  not  pene- 
trate much  beneath  the  surface  were  not  rendered  unfit  for  storage. 
Fruits  in  this  condition  from  sprayed  trees  were  placed  in  cold  stor- 
age for  the  sake  of  comparing  their  keeping  quality  with  that  of 
unblemished  specimens  of  the  same  varieties  from  the  same  trees. 
The  number  of  specimens  in  each  lot  was  as  follows : 

Lot  i.  Lot  2. 

Unblemished.  Worm-attacked. 

Grimes  35  24 

Fameuse    27  17 

Winesap    21  24 

Ben  Davis   23  22 

Examinations  were  made  at  intervals  during  the  season,  and  the 
following  notes  were  taken  regarding  the  condition  of  the  fruit. 

November  19: — 

Grimes :     Both  lots  perfectly  sound,  but   showing  some  slightly  withered 

specimens. 

Fameuse:     Lot   I    (unblemished).     Some  specimens     somewhat   withered; 
one  entirely  rotten;    two  showing  rotten  specks  where  skin  had  been 
broken.     (Only  the  entirely  rotten  specimen  was  removed.) 
Lot  2  (worm-attacked).     Some  specimens  somewhat  withered.     No  rotten 
apples.    Two  specimens  show  rotten  spots  where  skin  had  been  broken. 
One  of  these  has  two  rotten  spots,  one  of  which  is  at  a  worm  injury. 
Balance  keeping  perfectly  about  worm  injuries. 
Winesap:    Lot  I  (unblemished).     In  perfect  condition. 
Lot  2  (worm-attacked).     Keeping  perfectly  except  that  a  few  specimens 

are  slightly  withered. 

Ben  Davis:    Lot  I  (unblemished).    In  perfect  condition. 
Lot  2  (worm-attacked).     Keeping  perfectly  except  one  specimen  which  is 

beginning  to  rot  at  the  blossom  end. 
February  19 : — 

Grimes:     Lot  I    (unblemished).     No  rotten  apples,  and  none  with  rotten 
specks.     Quite  badly  withered. 


398  BULLETIN  No.  114.  [March, 

Lot  2  (worm-attacked).     Five  specimens  specked  with  rot,  one  specimen 

one-fourth  decayed,  eighteen  badly  withered  but  without  rot. 
Fameuse:    Lot  I  (unblemished).    One  specimen  shows  a  small  rotten  speck. 

All  other  specimens  are  withered,  but  not  rotting. 
Lot  2    (worm-attacked).     Four  specimens  about  half  rotten;    all  others 

badly  withered,  but  not  rotting. 
Winesap :     Lot  I   (unblemished).     Perfectly  sound.     None  withered. 

Lot  2  (worm-attacked).    No  rot.    A  few  specimens  slightly  withered. 
Ben  Davis:     Lot  I  (unblemished).     No  rot.     Keeping  well. 

Lot  2  (worm-attacked).     No  more  rot  than  November  19.     Keeping  well. 
March  18: — 

Grimes:  Lot  I  (unblemished).  Two  specimens  breaking  down,  two  badly 
spotted  with  rot,  two  slightly  spotted,  ten  badly  withered  but  not  rot- 
ting, nineteen  perfectly  sound  though  part  of  them  are  somewhat 
withered. 

Lot  2  (worm-attacked).  Four  specimens  badly  rotted,  five  specked  with 
rot,  seven  badly  withered  but  not  rotting,  eight  sound  (slightly  more 
withered  than  in  lot  i ) . 

Fameuse:  Lot  I  (unblemished).  Two  specimens  badly  decayed,  five  badly 
spotted  with  rot,  three  slightly  spotted,  six  badly  withered  but  not  rot- 
ting, ten  sound  but  slightly  withered. 

Lot   2    (worm-attacked).      Three    specimens   badly    decayed,   three    badly 
spotted  with   rot,  three  slightly  spotted,   eight   sound  but  considerably 
withered  (much  more  so  than  in  lot  i). 
Winesap:     Lot  I   (unblemished).     No  signs  of  rot.     Six  specimens  slightly 

withered,  fifteen  perfectly  sound  (not  withered). 

Lot  2   (worm-attacked).     No  signs  of  rot.     Two  specimens  badly  with- 
ered, seven  slightly  withered,  fifteen  perfectly  sound  (not  withered). 
Ben  Davis:     Lot   i    (unblemished).     One  specimen  slightly  spotted,  three 

slightly  withered,  nineteen  perfectly  sound  (not  withered). 
Lot  2    (worm-attacked).     Two  specimens  badly  spotted,-  four  somewhat 

withered,  sixteen  perfectly  sound  (not  withered). 
At  this  date  the  Grimes  and  Fameuse  were  withdrawn  from  storage. 
April  19: — 

Winesap:    Lot  I  (unblemished).     No  signs  of  rot.     Some  specimens  some- 
,    what  withered. 
Lot  2    (worm-attacked).     No  signs  of  rot.     Many  specimens   still   firm, 

but  on  the  average  slightly  more  withered  than  lot  I. 
Ben  Davis:     Lot   i    (unblemished).     One   specimen   slightly  spotted,   four 

somewhat  withered,  eighteen  perfectly  sound  and  firm. 
Lot  2  (worm-attacked).    Three  specimens  with  rotten  spots.    In  only  one, 
however,  does  the  rotten  area  surround  the  worm  injury.     One  speci- 
men scalded,  four  somewhat  withered,  fourteen  perfectly  sound  and  firm. 

These  notes  show  that  apples  attacked  by  the  second  brood  of 
the  codling  moth,  in  which  the  worm  stopped  before  going  deeply 
into  the  fruit,  kept  in  cold  storage  almost  as  well  as  fruits  which 
were  without  blemish,  the  chief  difference  being  that  the  blemished 
fruits  became  somewhat  more  withered  than  the  unblemished  speci- 
mens. When  the  fruits  began  to  decay,  the  rot  usually  did  not  start 
from  the  point  of  worm  injury,  and  was  nearly  as  prevalent  on  un- 
blemished as  blemished  specimens.  The  condition  of  the  Winesap 
and  Ben  Davis  at  the  end  of  the  storage  period  indicates  that  there 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH, 


399 


need  be  no  great  fear  of  loss  by  reason  of  rot  or  poor  keeping  of 
apples  injured  in  the  manner  specified,  in  the  case  of  long  keeping 
varieties. 


PIG.  4.    APPLES  ATTACKED  BY  SECOND  BROOD  OF  CODLING  MOTH. 


FIG.  5.    THE  SAME  FRUITS  AS  IN  FIG.  4,  CUT  OPEN  TO  SHOW  EXTENT  OF 

INJURY.    THE  WORM  STOPPED  CLOSE  TO  THE  SURFACE 

IN  THE  FRUIT  AT  THE  LEFT. 


400  BULLETIN  No.  114.  [March, 

Tables  n  and  12  (p.  396)  show  that  many  apples  were  injured 
in  the  manner  specified,  and  that  the  proportion  was  much  greater 
from  sprayed  than  unsprayed  trees ;  that  is,  a  much  larger  proportion 
of  the  apples  showing  evidences  of  insect  attack  were  only  slightly 
injured  and  not  rendered  unfit  for  storage  in  the  case  of  sprayed 
than  unsprayed  trees.  In  the  case  of  unsprayed  trees  it  is  evident 
that  the  worms  which  ceased  activities  and  disappeared  after  enter- 
ing the  apple  but  before  penetrating  deeply  into  the  flesh  must  have 
done  so  from  natural  causes,  but  the  fact  that  the  proportion  of 
worms  so  doing  was  so  much  larger  in  the  case  of  fruit  from  sprayed 
trees  indicates  that  at  least  part  of  these  worms  must  have  been  killed 
by  the  spray  after  they  entered  the  fruit.  It  will  be  remembered  that 
the  late  spraying  was  not  commenced  until  after  many  worms  had 
entered  the  fruit. 

LABORATORY-  INVESTIGATIONS 

Investigations  were  made  in  the  laboratory  to  determine  whether 
or  not  the  worms  could  be  killed  by  the  spray  in  the  manner  above 
suggested.  The  examination  of  windfalls  which  had  been  entered 
by  457  larvae  of  the  second  brood  showed  that  43.76  percent  of  these 
larvae  entered  at  the  side  of  the  apple,  33.48  percent  at  the  calyx, 
and  22.75  percent  close  to  the  stem.  Particular  attention  was  given 
to  studying  the  effect  of  a  poisonous  spray  upon  the  larvae  entering 
the  side  of  the  apple,  applied  after  they  had  entered. 

After  entering  an  apple,  the  worm  feeds  for  a  few  days  close  to 
the  surface,  usually  eating  in  a  circle  about  the  point  of  entrance, 
just  beneath  the  skin,  sometimes  even  eating  holes  through  the 
skin.  A  deposit  of  excrement  invariably  covers  the  point  of  en- 
trance and  increases  in  size  as  the  worm  continues  its  work.  When 
the  apple  is  sprayed,  a  drop  of  the  liquid  usually  lodges  on  or  in  the 
accumulation  of  excrement,  since  the  particles  of  the  latter  present 
a  rough  and  porous  mass  which  is  sure  to  absorb  and  hold  some  of 
the  liquid.  An  examination  of  sprayed  apples  revealed  the  presence 
of  numerous  particles  of  Paris  green  on  the  skin  of  the  apple  close 
about  the  outer  edge  of  the  mass  of  excrement  and  also  lodged 
among  its  particles. 

Six  apples  were  sprayed  in  the  laboratory  August  7,  by  means 
of  an  atomizer  charged  with  Paris  green  used  at  the  rate  of  one-half 
pound  to  50  gallons  of  water.  All  these  apples  had  been  entered  by 
worms.  Five  more  apples  were  sprayed  in  like  manner  August  9. 
In  this  case  the  Paris  green  was  used  at  the  rate  of  one  pound  to  50 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


401 


gallons.  August  12,  these  apples  were  examined  to  determine  the 
condition  of  the  worms.  The  larvae  were  carefully  sought  and  re- 
moved under  a  dissecting  microscope,  and  were  then  placed  on  a 
glass  slide  and  examined  under  a  compound  microscope.  If  they 
showed  no  signs  of  life,  they  were  designated  "dead;"  if  they 
showed  slight  signs  of  activity,  such  as  the  moving  of  the  jaws,  but 
seemed  weak  and  sick,  they  were  designated  "nearly  dead ;"  if  they 
wriggled  vigorously,  they  were  designated  "healthy."  In  all  cases, 
the  "dead"  and  "nearly  dead"  worms  were  close  to  the  surface  of 
the  fruit.  In  these  examinations  no  note  was  taken  as  to  whether 
the  healthy  worms  had  gone  to  the  interior  of  the  fruit  or  not.  The 
condition  of  the  worms  was  as  follows : 

Worms  dead    4 

Worms  nearly  dead   3 

Worms  healthy  9 


Total 


16 


Since  some  of  these  worms  had  been  in  the  apples  several  days 
and  had  probably  gone  to  the  interior  of  the  fruit  before  the  spray 
was  applied,  a  fresh  supply  of  apples  was  procured  from  the  orchard 
August  12,  and  sprayed  in  the  laboratory,  with  Paris  green  used  at 
the  rate  of  one  pound  to  50  gallons.  The  mixture  was  purposely 
made  much  stronger  than  it  would  be  used  in  orchard  operations. 
The  apples  were  divided  into  three  lots  of  seven  each.  In  lot  i,  the 
apples  had  been  very  recently  entered  by  the  worms;  in  lot  2,  the 
worms  had  entered  somewhat  earlier,  while  in  lot  3,  they  had  en- 
tered still  earlier,  so  that  some  of  them  may  have  gone  to  the  in- 
terior before  the  spray  was  applied.  These  apples  were  carefully 
examined  three  days  after  the  spray  was  applied.  The  condition 
of  the  worms  was  found  to  be  as  follows : 

TABLE  13.— CONDITION  OF  WORMS  IN  SPRAYED  APPLES 


Lot  1. 

Lot  2. 

Lot  3. 

Total. 

Dead  

5 

3 

4 

12 

Nearly  dead  

0 

1 

0 

1 

Healthy  (near  surface)  

1 

1 

1 

3 

Gone  to  interior  

0 

1 

2 

3 

Not  found  .  .      .  .         

1 

2 

0 

3 

Total  .  . 

7 

8 

7 

22 

In  all  cases  the  worms  which  had  gone  to  the  interior  were  ap- 
parently healthy.  One  of  the  dead  worms  in  lot  3  had  apparently 
been  killed  by  a  fungous  disease  rather  than  by  the  spray,  so  that 


402 


BULLETIN  No.  114. 


[March, 


the  total  number  of  worms  evidently  killed  by  the  spray  would  be 
eleven,  or  fifty  percent  of  the  worms  attacking  the  apples.  As  might 
have  been  expected,  a  larger  proportion  of  the  worms  succumbed  in 
the  case  of  apples  sprayed  very  soon  after  the  worms  had  entered. 
In  order  to  test  further  this  matter  and  to  make  sure  that  it  was 
the  Paris  green  which  caused  the  death  of  the  worms,  three  lots  of 
apples  were  again  selected,  and  sprayed  in  the  laboratory,  and  the 
same  number  in  a  similar  condition  in  each  case  left  unsprayed  as 
checks.  The  relative  ages  of  the  worms  in  the  various  lots  were 
the  same  as  in  the  previous  test.  The  examination  made  three  days 
after  the  spraying  was  done  showed  the  condition  of  the  worms  to 
be  as  follows : 


TABLE  14  — CONDITION  OF  WORMS  IN  SPRAYED  AND  UNSPRAYED  APPLES 


Dead  

Lotl. 

Lot  2. 

Lot3. 

Summary. 

•d 

| 

rt 

Q. 
X 

A 

1 

0 

i 

2 

o. 
en 

,* 
y 

<u 
a 
o 

•o 

9 
!>> 

2 

a, 

VI 

1 
-  as  o  o  o  Check. 

i 

>•> 

2 
a 
tn 

jj 

i 

a 
o 

2 
0 
1 
0 
0 

0 
0 
1 
2 
0 

1 
1 
1 

1 
0 

0 

0 
0 
4 
0 

2 
2 
2 
1 
0 

5 
3 
4 
2 
0 

0 
0 
1 
12 
1 

Nearly  dead  

Healthy  (near  surface) 
Gone  to  interior  

Killed  by  parasites  

Total  

3 

3 

4 

4 

7 

7 

14 

14 

Of  the  fourteen  worms  in  the  unsprayed  apples,  every  one,  ex- 
cept the  one  killed  by  parasites,  was  apparently  healthy,  while  of  the 
fourteen  worms  in  the  sprayed  apples,  only  six  were  in  a  like  condi- 
tion; and  there  seems  to  be  no  question  but  that  the  Paris  green 
was  the  cause  of  this  difference. 

The  laboratory  experiments,  then,  show  conclusively  that  it  is 
possible  to  kill  at  least  a  part  of  the  second  brood  larvae  of  the  codling 
moth  by  means  of  a  poisonous  spray  applied  even  after  the  worms 
have  entered  the  fruit.  However,  the  fruit  in  which  a  worm  is 
killed  near  the  surface  will  be  slightly  blemished,  and  although  it 
will  keep  fairly  well  in  cold  storage,  is  not  as  high  grade  a  product 
as  is  fruit  without  blemish.  This  indicates  that  although  an  apple 
crop  may  be  saved  from  utter  ruin  by  late  spraying  commenced  af- 
ter the  second  brood  worms  have  begun  to  enter  the  apples,  it  would 
be  much  better  to  kill  the  worms,  if  possible,  before  they  enter 
the  fruit. 


1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  403 

» 

INVESTIGATIONS  IN  1902 

In  1902,  the  spraying  was  commenced  before  any  worms  of  the 
second  brood  had  entered  the  apples,  with  a  view  to  reducing,  if 
possible,  the  percentage  of  fruit  slightly  damaged  by  worms  stopped 
near  the  surface.  An  attempt  was  also  made'  to  find  a  spraying 
mixture  that  would  be  effective  against  the  worms  and  at  the  same 
time  not  cause  excessive  dropping  of  the  fruit  by  reason  of  injury 
to  the  stems. 

For  the  purpose  of  this  experiment,  ten  trees,  five  each  of  Grimes 
and  Ben  Davis,  were  selected  July  10,  and  sprayed  on  the  same  day 
with  mixtures  made  according  to  the  formulas  indicated  below, 
there  being  one  tree  of  each  variety  under  each  of  the  different 
treatments.  All  these  trees  had  received  the  three  usual  applica- 
tions of  Bordeaux  and  Paris  green  in  the  spring. 


1.  Paris  green  J4  lb-»  l'me  about  2  lb.,  water  50  gal. 

2.  Paris  green  l/2  lb.,  lime  about  2  lb.,  water  50  gal. 

3.  Arsenate  of  lead  :   lead  acetate  121A  oz.,  soda  arsenate  5  oz.,  water  50  gal. 

4.  Double  strength  arsenate  of  lead  :    lead  acetate  25  oz.,   soda  arsenate  10 

oz.,  water  50  gal. 

5.  Check  —  no  late  spraying. 

For  making  the  arsenate  of  lead,  the  lead  acetate  and  soda  ar- 
senate were  each  dissolved  separately  in  small  quantities  of  cold 
water.  The  full  amount  of  water  for  the  complete  mixture  minus 
that  used  in  dissolving  the  salts  was  measured  out  into  a  large  ves- 
sel ;  then  the  solutions  were  added  separately  to  this  large  volume 
of  water,  which  was  stirred  thoroughly  while  they  were  being  slowly 
poured  in. 

The  Grimes  were  large  trees  over  twenty  years  old,  and  the  Ben 
Davis  were  small  trees  bearing  their  second  crop.  Twelve  and  one- 
half  gallons  of  material  were  mixed  in  each  case,  but  in  most  cases 
not  quite  all  of  the  mixture  was  used  in  spraying  the  two  trees. 

The  spray  was  applied  by  means  of  a  hand  pump  worked  at  high 
pressure,  and  carrying  only  one  lead  of  hose.  A  double  Vermorel 
with  fine  caps  was  the  nozzle  employed.  Particular  care  was  taken 
to  secure  as  nearly  as  possible  a  uniform  distribution  of  material 
over  all  parts  of  all  the  apples,  without  allowing  the  fine  drops  to 
run  together. 

Additional  applications  of  the  same  materials  were  made  to  the 
Grimes,  July  25  and  August  8,  and  to  the  Ben  Davis  July  25,  Aug- 
ust 8,  22,  and  September  5,  so  that  altogether  the  Grimes  received 
three  applications  for  the  second  brood  of  codling  moth,  and  the 


404 


BULLETIN  No.  114. 


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Percentage  of  windfalls  injure 
moth  
Percentage  of  windfalls  appa 
stem  

1907. J  SPRAYING  FOR  THE  CODLING  MOTH.  405 

Ben  Davis  five  applications.  All  applications  were  made  in  the  same 
manner  and  with  equal  thoroughness. 

July  12,  the  ground  under  the  trees  was  cleared  of  fallen  apples 
of  every  description,  so  that  a  record  could  be  kept  of  all  apples 
falling  after  that  date.  These  were  picked  up  at  intervals  through 
the  season,  counted,  and  examined  for  insect  injuries  and  also  in- 
juries to  the  stem  apparently  caused  by  the  spray.  Table  15  gives 
a  summary  of  the  records,  and  includes  all  apples  which  fell  from 
the  trees  from  July  12  until  the  hand-picked  crop  was  harvested. 

It  will  be  seen  that  some  of  the  windfalls  from  unsprayed  trees 
are  designated  as  "apparently  injured  by  spray  at  stem."  It  is  evi- 
dent that  such  injury  could  not  have  been  caused  by  the  spray,  since 
the  trees  were  not  sprayed.  However,  the  stems  were  brown  and 
dead,  and  the  injury  could  not  be  distinguished  from  that  to  the 
stems  of  apples  from  the  sprayed  trees  in  the  case  of  specimens  in 
which  the  injury  was  confined  to  the  stem  itself.  It  is  probable 
that  some  of  the  stem  injury  to  apples  from  sprayed  trees  was  not 
due  to  the  spray.  However,  the  fact  that  the  percentage  of  stem- 
injured  fruit  was  much  greater  for  sprayed  than  unsprayed  trees 
indicates  that  the  spray  must  have  caused  much  of  the  injury. 
Furthermore  the  high  percentage  of  sound  fruit  among  the  wind- 
falls from  sprayed  trees,  especially  those  sprayed  with.  Paris  green, 
suggests  that  the  spray  must  have  caused  the  falling  of  much  of 
this  fruit. 

That  the  Paris  green,  especially  the  stronger  mixture,  did  cause 
an  excessive  dropping  of  the  fruit  is  clearly  shown  by  the  following 
figures  which  represent  in  each  case  the  percentage  of  the  total  num- 
ber of  apples  on  the  tree  July  12  which  dropped  before  the  hand- 
picked  crop  was  harvested. 

TABLE  16.— PERCENTAGE  OF  CROP  WHICH  PELL  BEFORE  MATURITY,  1902 


Treatment. 

Grimes. 

Ben 
Davis. 

1 

Paris  green,  /^  lb.  to  50  gal.,  with  lime  

25.27 

35.65 

2 

Paris  green,  %  lb.  to  50  gal.,  with  lime  

45.61 

47.02 

3 

Arsenate  of  lead  

17.36 

13.26 

4 

Arsenate  of  lead,  double  strength  

10.02 

15.65 

5. 

Check  —  no  late  spraying  

35.02 

21.03 

The  crop  of  Grimes  was  picked  from  the  trees  September  9  and 
10,  and  the  Ben  Davis  October  J.  The  apples  were  carefully  sorted 
and  counted.  All  specimens  showing  any  indication  of  worm  in- 


406 


BULLETIN  No.  114. 


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tage  injured  for  storage  by  secon< 
h  
:age  in  which  worms  stopped  near 
tage  injured  by  first  brood  only.  .  .  . 
:age  uninjured  for  storage  by  codl 
ads)  
tage  of  the  apples  attacked  by  t 
ch  worms  stopped  near  surface.  .  . 

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1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  407 

jury  were  critically  examined,  and  unless  it  was  perfectly  evident 
that  the  worm  had  been  stopped  close  to  the  surface  of  the  fruit  so 
that  the  apple  had  not  been  injured  for  storage  purposes,  the  speci- 
men was  cut  open  in  order  to  determine  the  exact  extent  of  the 
injury.  The  results  of  the  examination  of  the  entire  hand-picked 
crop  from  each  of  the  ten  trees  are  given  in  Table  17.  Injuries 
other  than  those  caused  by  the  second  brood  of  the  codling  moth 
were  recorded  only  in  the  case  of  specimens  not  visibly  attacked  by 
the  second  brood,  and  in  no  case  was  more  than  one  injury  recorded 
against  the  same  specimen.  All  injuries  are  entered  in  the  table 
in  the  order  of  their  precedence,  the  most  important  or  worst  in- 
juries, from  the  standpoint  of  this  investigation,  preceding  those  of 
less  importance. 

These  figures  show  that  in  both  varieties  and  under  all  treat- 
ments, the  spraying  caused  a  decrease  in  the  percentage  of  fruits 
visibly  attacked  by  the  second  brood  of  the  codling  moth.  Although 
the  percentage  of  apples  slightly  damaged  by  codling  moth  stopped 
near  the  surface  was  not  as  small  as  could  have  been  desired,  never- 
theless the  fact  that  in  a  much  larger  percentage  of  the  apples  vis- 
ibly attacked  the  worms  were  stopped  near  the  surface  in  the  case 
of  fruit  from  sprayed  than  unsprayed  trees,  indicates  a  marked  bene- 
fit from  spraying,  and  corroborates  the  results  of  the  preceding  year 
in  so  far  as  they  apply  to  the  feasibility  of  killing  the  worms  after 
they  have  entered  the  fruit.  The  percentage  of  the  entire  hand- 
picked  crop  uninjured  for  storage  by  the  codling  moth,  including  the 
work  of  both  broods,  is  much  larger  for  the  sprayed  trees,  under 
every  treatment,  than  for  the  unsprayed  trees. 

The  above  considerations  refer  merely  to  the  hand-picked  fruit. 
Reference  has  already  been  made  to  the  excessive  dropping  of  fruit 
from  certain  of  the  sprayed  trees.  In  order  to  make  a  fair  com- 
parison of  the  results  of  different  treatments,  it  is  essential  that  the 
windfalls  as  well  as  the  hand-picked  fruit  be  considered.  So  far  as 
suitability  for  storage  is  concerned,  all  the  windfalls  may  be  put  in 
one  class,  regardless  of  the  cause  or  exact  time  of  their  falling.  The 
net  crop  really  consists  of  the  hand-picked  fruit  suitable  for  storage. 
So  far  as  this  investigation  is  concerned,  a  true  comparison  of  the 
different  treatments  can  best  be  made  by  considering  as  suitable  for 
storage  all  hand-picked  specimens  which  have  not  been  rendered 
unfit  for  storage  by  the  work  of  the  codling  moth.  If  the  percent- 
age of  the  apples  on  the  trees  July  12  which  remained  uninjured 
for  storage  by  the  codling  moth  until  gathered  as  hand-picked  fruit 
be  taken  as  the  basis  of  comparison,  the  true  relative  merits  of  the 


408 


BULLETIN  No.  114. 


[March, 


different  treatments  may  readily  be  determined.     Compared  on  this 
basis,  the  results  appear  as  follows : 

TABLE  19.— PERCENTAGE  OF  TOTAL  CROP  UNINJURED  FOR  STORAGE  BY 

CODLING  MOTH,  1902 


Treatment. 

Second  brood. 

Both  broods. 

Grimes. 

Ben 

Davis. 

Grimes. 

Ben 
Davis. 

1. 
2. 

3. 
4. 
5. 

.Paris  green,  %  Ib.  to  50  gal.,  with 
lime  

61.65 

47.38 
74.98 
82  50 
4H.67 

63.04 

51.33 
81.63 
81.45 
49.09 

60.85 

46.71 
74.44 
81^9 
43.05 

63.04 

50.92 
79.93 
80.58 
48.83 

Paris  green,  %  Ib.  to  50  gal.,  with 
lime  

Arsenate  of  lead  

Arsenate  of  lead,  double  strength 
Check  —  no  late  spraying  

It  will  be  seen  that  the  stronger  mixture  of  Paris  green  gave 
but  slightly  better  net  results  than  no  late  spraying  whatever.  This 
was  due  to  the  excessive  dropping  of  the  immature  fruit.  The  use 
of  the  weaker  mixture  of  Paris  green  materially  increased  the  per- 
centage of  fruit  suitable  for  storage,  but  the  arsenate  of  lead  gave 
decidedly  better  results  than  the  Paris  green  used  at  either  strength. 
The  double  strength  arsenate  of  lead  seemed  more  effective  on  the 
Grimes  than  the  usual  strength,  though  on  the  Ben  Davis,  where 
five  applications  were  made,  the  net  results  from  the  use  of  the  two 
mixtures  were  practically  identical. 

INVESTIGATIONS  IN  1903 

The  results  of  the  work  in  1902  plainly  indicated  that  one-half 
pound  of  Paris  green  to  50  gallons  of  water,  even  when  used  with 
lime,  was  too  strong  a  mixture  to  be  applied  to  bearing  apple  trees 
in  midsummer.  This  treatment  was  therefore  not  used  in  1903. 
Since  it  is  often  advisable  to  spray  with  a  fungicide  late  in  the  sea- 
son, it  was  thought  best  to  test  the  efficiency  of  Paris  green  used  in 
combination  with  Bordeaux  mixture  as  compared  with  Paris  green 
and  lime  and  with  arsenate  of  lead.  The  following  treatments  for 
the  second  brood  of  codling  moth  were  therefore  tested  in  1903. 

1.  Paris  green  %  Ib.,  lime  4  Ib.,  water  50  gal. 

2.  Paris  green  %  Ib.,  lime  4  Ib.,  copper  sulphate  4  Ib.,  water  50  gal. 

3.  Arsenate  of  lead. 

4.  Arsenate  of  lead,  double  strength. 

5.  Check — no  late  spraying. 

The  trees  used  for  this  experiment  were  the  Grimes.  All  had 
received  the  three  usual  applications  of  Bordeaux  mixture  and  Paris 
green  in  the  spring.  The  method  of  application  employed  in  the  late 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


409 


spraying  was  the  same  as  in  1902.  Applications  were  made  July 
17  and  27,  August  10  and  24.  No  larvae  of  the  second  brood  of 
codling  moth  had  been  seen  in  the  orchard  up  to  the  time  of  the  first 
application. 

All  fallen  apples  under  the  trees  were  gathered  the  day  the  first 
application  was  made,  and  a  record  was  kept  of  all  apples  falling 
after  that  date,  except  that  the  record  for  the  check  tree  (No.  5)  is 
incomplete  on  account  of  one  of  the  workmen  picking  up  the  wind- 
falls August  10,  and  mixing  them  with  those  from  other  trees  in 
the  orchard.  This  makes  it  impossible  to  determine  the  relative 
percentage  of  drop  from  the  sprayed  and  unsprayed  trees,  but  does 
riot  interfere  with  the  comparison  between  the  sprayed  trees  under 
different  treatments.  Table  20  gives  a  summary  of  the  examina- 
tion of  windfalls. 


TABLE  20.— EXAMINATION  OF  WINDFALLS,  1903 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

Apples  apparently  injured  by  spray  at  stem 
Sound  

152 
61 

300 
105 

255 
96 

609 
147 

289 
33 

Sound  except  for  spray  injury  at  stem  
Total  sound  

31 

92 

39 
144 

20 
116 

79 

226 

10 
33 

Injured  by  first  brood  codling  moth  

139 

392 

311 

499 

330 

Injured  by  curculio  

33 

63 

50 

49 

68 

Injured  by  second  brood  codling  moth: 
Entering  at  calyx  

85 

234 

258 

336 

350 

Entering  at  stem  

14 

40 

67 

58 

102 

Entering  at  side  .... 

30 

60 

78 

83 

27 

Total  injured  by  second  brood  codling 
moth  

129 

334 

403 

477 

479 

Otherwise  injured  

1 

18 

18 

37 

43 

Total  number  of  windfalls  

434 

1009 

945 

1374 

1067 

Percentage  of  windfalls  which  were  sound 
Percentage  of  windfalls  injured  by  second 
brood  codling  moth  

21.19 
29.72 

14.27 
33.10 

12.27 
42.64 

16.44 
34.71 

3.09 

44.89 

Percentage  of  windfalls  apparently  injured 
by  spray  at  stem  

35,02 

29.73 

26.98 

44.32 

27.08 

It  will  be  seen  that  a  much  larger  proportion  of  the  windfalls 
were  infested  with  codling  moth  than  was  the  case  in  1902,  and 
that  injuries  caused  by  the  first  brood  as  well  as  the  second  were 
very  much  in  evidence.  This  suggests  that  the  early  spraying,  be- 
fore the  trees  were  selected  for  the  experiment,  was  not  as  effective 
as  it  should  have  been.  This  spraying  did  not  have  special  super- 
vision, and  no  statement  can  be  made  regarding  its  thoroughness. 
The  injury  to  the  stems  was,  on  the  whole,  less  apparent  than  in 
1902,  though  the  double  strength  arsenate  of  lead  seemed  to  result 


410 


BULLETIN  No.  114. 


[March, 


in  more  injury  than  in  the  preceding  year.  The  percentage  of  the 
crop  on  the  trees  July  17,  which  dropped  before  maturity,  was  in 
each  case  as  follows : 


TABLE  21.— PERCENTAGE  OF  CROP  WHICH  FELL  BEFORE  MATURITY,  1903 


Treatment. 

1.  Paris  green,  with  lime  

33.46 

2.  Paris  green,  with  Bordeaux  mixture  

28.64 

3.  Arsenate  of  lead  

35.83 

4.  Arsenate  of  lead,  double  strength  

30.72 

In  spite  of  the  greater  proportion  of  stem-injured  fruits  among 
the  windfalls  from  the  trees  sprayed  with  the  double  strength  ar- 
senate  of  lead,  the  proportion  of  the  crop  which  dropped  was  less 
than  for  any  of  the  other  treatments  except  the  Paris  green  with 
Bordeaux  mixture.  This  treatment  resulted  in  the  smallest  percent- 
age of  dropped  fruit  and  showed  also  a  comparatively  low  percent- 
age of  stem  injury. 

The  apples  from  the  trees  in  this  experiment  were  picked  Sep- 
tember 8  and  9.  The  same  method  of  examination  of  the  hand- 
picked  fruit  was  employed  as  in  1902,  except  that  in  addition,  notes 
were  made  as  to  the  points  of  entrance  of  the  second  brood  larvae.  A 
summary  of  the  results  of  the  examination,  corresponding  to  the 
items  given  for  1902,  is  given  in  Table  22. 

TABLE  22 —EXAMINATION  OF  HAND-PICKED  CROP  FROM  TREES  SPRAYED 
FOR  SECOND  BROOD  CODLING  MOTH,  1903 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

Total  number  of  apples  

863 

2513 

1692 

^OQ8 

2^87 

Visibly  attacked  by  second  brood  codling 
moth: 
Injured  for  storage  by  second  brood  cod- 
ling moth  

317 

819 

8%?8 

1079 

1007 

Worm  found  in  apple  

163 

331 

373 

517 

392 

Worm  gone  to  interior  but  not  found: 
Fruit  badly  damaged  

105 

300 

280 

363 

487 

Fruit  not  badly  damaged  

49 

188 

175 

199 

128 

Uninjured  for   storage    (worm  stopped 
near  surface)  

80 

112 

129 

222 

102 

Injured  by  first  brood  of  codling  moth  

55 

145 

139 

199 

87 

Injured  by  curculio  

78 

354 

181 

339 

672 

Bird-picked,  rotting  or  otherwise  injured.  . 
Sound  

4 

329 

26 
1057 

15 

400 

29 
1230 

60 
459 

Reduced  to  percentages,  the  figures  in  reference  to  codling  moth 
injuries  appear  as  follows  : 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


411 


TABLE  23. — PERCENTAGE  OF  HAND-PICKED  CROP  INJURED  BY  CODLING 

MOTH,  1903 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

Percentage  visibly  attacked  by  second 
brood  codling  moth  

46.00 

37.04 

56.56 

-41.99 

46.42 

Percentage  injured  for  storage  by  second 
brood  codling  moth  

36.73 

32.59 

48.93 

34.82 

42.15 

Percentage  in  which  worms  stopped  near 
surface  

9.27 

4.45 

7.63 

7.17 

4.27 

Percentage  injured  by  first  brood  only  

6.37 

5.77 

8.21 

6.42 

3.64 

Percentage  uninjured  for  storage  by  cod- 
ling moth  (both  broods)  

56.90 

61.64 

42.86 

58.76 

54.21 

Percentage  of  the  apples  attacked  by  sec- 
ond brood,  in  which  worms  stopped  near 
surface.  . 

20.15 

12.03 

13.48 

17.06 

9.19 

These  figures  show  that  the  spraying  was  much  less  effective 
than  in  1902.  Mention  has  already  been  made  of  the  fact  that  the 
first  brood  of  codling  moth  was  not  controlled  by  the  early  spraying 
This  would  naturally  result  in  a  severe  attack  of  the  second  brood. 
Furthermore,  if  worms  of  the  first  brood,  which  normally  enter  the 
apples  mainly  by  way  of  the  calyx,  were  able  to  gain  entrance  with- 
out being  poisoned,  it  is  evident  that  worms  of  the  second  brood 
which  sought  entrance  at  the  calyx  would  be  safe  from  injury  so 
far  as  any  poison  remaining  from  the  early  applications  was  con- 
cerned. In  1903,  a  much  larger  proportion  of  the  second  brood 
entered  by  way  of  the  calyx  than  in  1902.  If  all  the  windfalls  in- 
jured by  second  brood  codling  moth  from  the  Grimes  trees  receiving 
no  late  spraying  are  considered,  the  percentages  injured  by  attack 
at  the  different  points,  for  the  two  years,  were  as  follows : 

Year.  At  calyx.     At  stem.      At  side. 

1902   44-90  19.60  35.49 

1903    73-07  21.29  5.63 

The  fact  that  a  very  large  proportion  of  the  injuries  due  to  the 
second  brood  of  codling  moth  were  caused  by  worms  entering  at  the 
calyx  is  further  illustrated  by  the  records  regarding  the  examination 
of  the  hand-picked  fruit.  Of  the  fruits  injured  for  storage  by  the 
second  brood  of  the  codling  moth,  the  following  percentages  were 
attacked  at  the  calyx  end : 

No.  i.        No.  2.        No.  3.        No.  4.        No.  5. 
54.25          65.44          75.24          62.92          72.49 

Under  these  conditions  it  is  not  surprising  that  the  late  spraying 
was  less  effective  than  in  1902. 

The  percentage  of  the  crop  on  the  trees  July  1 7,  which  remained 
uninjured  for  storage  by  the  codling  moth  was  as  follows : 


412  BULLETIN  No.  114.  [March, 

TABLE  24. — PERCENTAGE  OF  TOTAL  CROP  UNINJURED  FOR  STORAGE  BY 
CODLING  MOTH,  1903 


Treatment. 

Second 
brood. 

Botn 
broods. 

1.  Paris  green.  %  Ib.  to  50  gal.,  with  lime  

4.9  OQ 

Q7    Oft 

2.  Paris  green,  %  Ib.  to  50  gal.,  with  Bordeaux  

4.0  no 

4.1  Q8 

3.  Arsenate  of  lead  

•jo  7  A 

97   4Q 

4    Arsenate  of  lead,  double  strength  

AK     1  A 

4ft  fiQ 

These  figures  show  that  the  best  net  results  were  secured  from 
the  use  of  Paris  green  in  combination  with  Bordeaux  mixture, 
though  the  double  strength  arsenate  of  lead  proved  nearly  as  ef- 
fective. 


Since  it  seemed  probable  that  the  failure  to  secure  more  marked 
results  from  the  late  spraying  in  1903,  was  due,  at  least  in  part,  to 
a  lack  of  thoroughness  in  the  early  spraying,  the  trees  designed  for 
the  work  in  1904  were  selected  while  in  bloom,  and  thereafter 
sprayed  under  careful  supervision.  The  trees  were  comparatively 
young  Winesaps,  and  had  been  sprayed  once  with  Bordeaux  mixture 
and  .Paris  green  before  the  blossoms  opened.  After  the  petals  had 
fallen,  the  two  usual  applications  of  Bordeaux  mixture  and  Paris 
green  were  made.  However,  a  difference  was  made  in  the  amount 
of  material  used  and  the  method  of  application  for  different  trees. 
Seven  trees  were  given  a  light  application,  the  spraying  being  stop- 
ped before  the  fine  drops  ran  together;  and  seven  others  were 
sprayed  very  heavily.  The  plan  for  the  late  spraying  was  to  use 
one  tree  in  each  of  these  lots  for  each  of  several  different  treatments, 
including  those  employed  the  preceding  year.  However,  the  trees 
set  so  little  fruit  that  it  seemed  best  to  treat  them  all  alike  in  ref- 
erence to  the  late  spraying,  in  order  to  have  sufficient  fruit  under 
each  treatment  to  furnish  a  fair  test  regarding  the  influence  of  the 
method  of  the  early  applications  upon  the  control  of  the  second 
brood  of  the  codling  moth.  The  fourteen  trees  were  therefore 
sprayed  with  Paris  green  and  dilute  Bordeaux  mixture  July  20  and 
30,  and  August  10  and  26.  The  formula  used  in  making  the  mix- 
ture was  y^  pound  Paris  green,  4  pounds  lime,  2,  pounds  copper  sul- 
phate, 50  gallons  water.  The  method  of  application  was  the  same 
as  in  1902  and  1903.  The  ground  was  cleared  of  windfalls  July  19, 
and  thereafter  a  record  kept  of  all  the  apples  which  fell,  the  product 
of  the  seven  trees  under  each  treatment  being  considered  as  one  lot. 


1907.' 


SPRAYING  FOR  THE  CODLING  MOTH. 


413 


There  appeared  to  be  little  injury  to  the  stems,  and  no  record  re- 
garding that  point  was  kept.  The  fallen  fruit  was  carefully  exam- 
ined for  worm  injuries,  and  records  kept  regarding  the  point  of 
entrance  of  the  first  brood  as  well  as  the  second.  A  summary  of 
the  results  is  given  in  Table  25. 

TABLE  25.— EXAMINATION  OF  WINESAP  WINDFALLS,  1904 


Early  applications. 

Light. 

Heavy. 

Sound  

243 

92 
5 
24 
121 
15 

85 
15 
118 
218 
26 

623 
39.00 
19.42 

76.03 
34  .'99 

38.99 

584 

52 
2 
32 
86 
23 

62 
22 
192 
276 
60 

1029 
56.75 
8.35 

60.46 
26.82 

22.46 

Injured  by  first  brood  codling  moth: 
Entering  at  calyx  

Entering  at  stem  

Entering  at  side  

Total  injured  by  first  brood  codling  moth  

Injured  by  curculio  

Injured  by  second  brood  codling  moth: 
Entering  at  calyx  

Entering  at  stem  

Entering  at  side  

Total  injured  by  second  brood  codling  moth  

Otherwise  injured  

Total  number  of  windfalls  

Percentage  of  windfalls  which  were  sound  

Percentage  of  windfalls  injured  by  first  brood  cod 
ling  moth  

Percentage  of  the  windfalls  injured  by  first  brood 
codling  moth  in  which  the  worm  entered  at  the 
calyx  

Percentage  of   windfalls  injured  by  second  brood 
codling  moth  

Percentage  of  the  windfalls  injured  by  second  brood 
codling  moth  in  which  the  worm  entered  at  the 
calyx  

The  windfalls  from  the  trees  receiving  the  heavy  early  applica- 
tions showed  less  worm  injury  from  the  first  brood  and  also  from 
the  second,  and  there  was,  in  the  case  of  both  broods,  a  smaller  per- 
centage of  injury  due  to  worms  entering  at  the  calyx. 

The  percentage  of  the  total  crop  on  the  trees  July  19,  which  fell 
before  October  15,  when  the  hand-picked  fruit  was  gathered,  was 
for  the  trees  receiving  the  light  early  applications  45.77  percent,  and 
for  those  receiving  the  heavy  early  applications  27.86  percent.  This 
shows  a  decided  advantage  in  favor  of  the  heavy  early  spraying. 

The  hand-picked  apples  were  carefully  sorted  and  examined  for 
codling  moth  injuries,  and  a  complete  record  made  as  to  the  number 
of  worms  entering  at  the  various  points  and  the  extent  of  injury  in 
each  case.  The  results  of  this  examination  are  given  in  Table  26, 


414 


BULLETIN  No.  114. 


[March, 


TABLE  26. — EXAMINATION  OF  HAND-PICKED  CROP  FROM  WINESAP  TREES 
SPRAYED  FOR  CODLING  MOTH,  1904 


Early  applications. 


Light. 


Heavy. 


Total  number  of  apples 738 

Visibly  attacked  by  second  brood  codling  moth  at 
calyx: 

Injured  for  storage 20 

Worm  found  in  apple 14 

Worm  gone  to  interior  but  not  found: 

Fruit  badly  damaged 0 

Fruit  not  badly  damaged 6 

Uninjured  for  storage  (worm  stopped  near  sur- 
face)   72 

Visibly  attacked  by  second  brood  codling  moth  at 
stem: 

Injured  for  storage 1 

Worm  found  in  apple 0 

Worm  gone  to  interior  but  not  found: 

Fruit  badly  damaged 0 

Fruit  not  badly  damaged 1 

Uninjured  for  storage  (worm  stopped   near  sur- 
face)   0 

Visibly  attacked  by  second  brood  codling  moth  at 
side: 

Injured  for  storage 66 

Worm  found  in  apple 6 

Worm  gone  to  interior  but  not  found: 

Fruit  badly  damaged 8 

Fruit  not  badly  damaged 52 

Uninjured  for  storage  (worm  stopped  near  sur- 
face)    32 

Injured  by  first  brood  codling  moth 11 

Entering  at  calyx 10 

Entering  at  stem 0 

Entering  at  side 1 

Injured  by  curculio 2 

Sound. .  534 


2664 


18 

7 


82 


107 

18 

19 
70 

54 
9 
3 
0 
6 
3 
2384 


If  these  items  are  summarized  to  correspond  with  the  tables 
given  for  preceding  years,  the  figures  appear  as  follows : 

TABLE  27.— SUMMARY  OF  EXAMINATION  OF   HAND-PICKED  FRUIT  FROM 

WINESAP  TREES,  1904 


Early  Applications. 


Light. 


Heavy. 


Total  number  of  apples 

Visibly  attacked  by  second  brood  codling  moth: 

Injured  for  storage  by  second  brood  codling  moth 

Worm  found  in  apple 

Worm  gone  to  interior  but  not  found  : 

Fruit  badly  damaged 

Fruit  not  badly  damaged 

Uninjured  for  storage  (worm  stopped  near  surface). 

Injured  by  first  brood  codling  moth 

Injured  by  curculio 

Sound. . 


738 

87 
20 


59 

104 

11 

2 
534 


2664 

130 

27 

22 

81 

138 

9 

3 

2384 


1907. \ 


SPRAYING  FOR  THE  CODLING  MOTH, 


415 


TABLE  28.— PERCENTAGE  OF  HAND-PICKED  WINESAPS  INJURED  BY  COD- 
LING MOTH,  1904 


Percentage  visibly  attacked  by  second  brood  cod- 
ling moth 

Percentage  injured  for  storage  by  second  brood  cod- 
ling moth 

Percentage  in  which  worms  stopped  near  surface. . . 

Percentage  injured  by  first  brood  only 

Percentage  uninjured  for  storage  by  codling  moth 
(both  broods) 

Percentage  of  the  apples  attacked  by  second  brood, 
in  which  worms  stopped  near  surface 

Percentage  of  the  apples  injured  for  storage  by 
second  brood  codling  moth,  which  were  entered 
at  calyx 


Early  Applications. 


Light. 

Heavy. 

25.88 

10.06 

11.78 
14.09 
1.49 

4.87 
5.18 
.33 

86.73 

94.80 

54.45 

51.49 

22.98 

13.84 

It  will  be  seen  that  so  far  as  the  hand-picked  fruit  is  concerned, 
the  trees  which  received  the  heavy  early  applications  showed  much 
less  injury  from  the  second  brood  of  the  codling  moth  than  did 
those  receiving  the  light  early  applications.  Applying  the  final  test, 
the  percentage  of  the  entire  crop  on  the  trees  July  19,  which  re- 
mained until  the  harvest  as  specimens  uninjured  for  storage  by  the 
codling  moth,  the  following  figures  are  secured : 

TABLE  29.— PERCENTAGE  OF  TOTAL  CROP  OP  WINES.VPS  UNINJURED  FOR 
STORAGE  BY  CODLING  MOTH,  1904 


Second  brood. 

Both  broods. 

Light  early  applications  

47.83 

47  02 

Heavy  early  applications  

68.61 

68.37 

Viewed  from  every  standpoint,  the  heavy  spraying  early  in  the 
season  gave  decidedly  better  results  than  the  light  spraying,  in  ref- 
erence to  the  control  of  the  second  brood  of  the  codling  moth,  even 
though  all  trees  were  treated  alike  in  the  late  sprayings. 

After  it  was  decided  not  to  use  the  Winesap  trees  for  testing 
different  materials  applied  late  in  the  season,  six  Ben  Davis  trees 
that  were  well  loaded  with  fruit  were  selected  for  this  purpose. 
These  trees  had  been  sprayed  twice  after  the  petals  had  fallen,  but 
the  first  application  was  made  rather  late,  so  that  it  is  probable  that 
many  worms  of  the  first  brood  had  escaped  destruction  and  that 
many  apples  were  left  unprotected  against  worms  of  the  second 
brood  attacking-  the  fruit  at  the  calyx.  The  usual  mixture  of  Bor- 


416 


BULLETIN  No.  114. 


[Jf arc/i, 


deaux  and  Paris  green  had  been  used  in  the  early  spraying.  For 
the  second  brood  of  the  codling  moth,  these  trees  were  sprayed  four 
times,  the  dates  being  the  same  as  in  the  case  of  the  Winesap.  The 
treatments  given  and  the  percentages  of  the  fruit  which  fell  before 
maturity  were  as  follows : 

TABLE  30. — PERCENTAGE  OF  CROP  WHICH  FELL  BEFORE  MATURITY,  BEN 

DAVIS,  1904 


Treatment. 

1 

Paris  Green,  %  Ib.  to  50  gal.,  with  lime  

25.49 

2 

Paris  Green,  %  Ib.  to  50  gal.,  with  Bordeaux  

20.47 

•1 

Arsenate  of  lead  

23.63 

4 

Arsenate  of  lead,  double  strength  

19.30 

5 

Check  —  no  late  spraying  

31.69 

Paris  green,  J£  Ib.  to  50  gal.,  with  dilute  Bordeaux  

17.42 

The  examination  of  the  windfalls  revealed  injuries  as  noted  in 
the  following  table : 

TABLE  31.— EXAMINATION  OF  BEN  DAVIS  WINDFALLS,  1904 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

No.  6 

Sound  

350 

240 

308 

259 

91 

183 

Injured  by  first  brood  codling  moth: 
Entering  at  calyx  

262 

156 

170 

127 

104 

74 

Entering  at  stem  

3 

9 

9 

6 

7 

5 

Entering  at  side  

57 

58 

64 

31 

29 

38 

Total  injured  by  first  brood  codling 
moth  

322 

223 

243 

164 

140 

117 

Injured  by  curculio  

26 

11 

14 

25 

8 

13 

Injured  by  second  brood  codling  moth 
Entering  at  calyx  ". 

311 

192 

241 

160 

244 

149 

Entering   at  stem  

32 

33 

48 

37 

101 

18 

Entering  at  side  

153 

87 

135 

88 

177 

64 

Total  injured  by  second  brood  codling 
moth  

496 

312 

42-1 

285 

522 

231 

Otherwise  injured  

20 

17 

5 

27 

11 

12 

Total  number  of  windfalls  

1214 

803 

994 

760 

772 

556 

Percentage  of  windfalls  which  were 
sound  

28.83 

29.88 

30.98 

34.07 

11.78 

32.91 

Percentage  of   windfalls  injured  by 
first  brood  codling  moth  

26  52 

27.77 

24.44 

21.57 

18.13 

21.04 

Percentage   of  windfalls  injured  by 
second  brood  codling"  moth... 

40.85 

38.85 

42.65 

37.50 

67.61 

41.54 

These  figures  show  that  a  much  larger  percentage  of  the  wind- 
falls from  the  tree  receiving  no  late  spraying  were  injured  by  the 


1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


417 


second  brood  codling  moth  than  of  those  from  any  of  the  sprayed 
trees.  The  examination  of  the  windfalls  from  the  tree  receiving  no 
late  spraying  shows  that  of  the  apples,  injured  by  the  second  brood 
codling  moth,  47.65  percent  were  entered  at  the  calyx,  17.77  per- 
cent near  the  stem,  and  34.57  percent  at  the  side. 

The  hand-picked  crop  of  Ben  Davis  was  gathered  October  i. 
The  apples  were  carefully  sorted  on  the  basis  of  codling  moth  in- 
juries though  no  record  was  made  as  to  whether  the  injuries  were 
caused  by  worms  of  the  first  or  the  second  brood.  The  apples  des- 
ignated as  "worm  injured"  included  all  specimens  attacked  by  the 
codling  moth  (of  either  brood),  except  those  in  which  the  worms 
had  stopped  close  to  the  surface  without  noticeably  disfiguring  the 
fruit.  Specimens  in  which  the  worms  had  not  penetrated  much 
beneath  the  surface,  but  which  were  at  all  badly  disfigured,  even 
though  the  injury  was  healed  over,  and  specimens  showing  fresh 
worm  attacks,  indicating  the  possible  presence  of  the  live  worm  even 
though  close  to  the  surface,  were  considered  as  worm-injured.  None 
of  the  specimens  were  cut  open  to  determine  the  exact  extent  of  the 
injury,  but  all  were  very  carefully  scrutinized  during  the  sorting. 
The  results  of  this  grading  were  as  follows : 


TABLE  32.— EXAMINATION   OP  HAND-PICKED  BEN  DAVIS  SPRAYED  FOR 

CODLING  MOTH,  1904 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

No.  6 

Total  number  of  apples  

3548 

3119 

3213 

3177 

1664 

2634 

Injured  for  storage  by  codling  moth.. 
Percentage  of   hand-picked  crop  in- 
jured for  storage  by  codling  moth 
(both  broods)  

1893 
53.35 

1095 
35.10 

1302 
40.52 

1010 
31  79 

1146 

68.87 

931 
35.34 

Percentage  uninjured  for  storage  

46.65 

64.90 

59.48 

68.21 

31.13 

64.66 

The  percentage  of  hand-picked  fruit  injured  for  storage  by  the 
codling  moth  was  much  greater  in  the  case  of  the  tree  which  re- 
ceived no  late  spraying  than  for  any  of  the  sprayed  trees.  The  Paris 
green  gave  better  results  when  used  in  combination  with  Bordeaux 
mixture,  either  standard  or  dilute,  than  when  used  with  lime.  The 
double  strength  arsenate  of  lead  gave  considerably  better  results 
than  the  ordinary  strength. 

The  net  results  from  each  treatment  -(i.  e.,  the  percentage  of  the 
crop  on  the  trees  July  19  which  remained  to  be  hand-picked  as  fruit 


418 


BULLETIN  No.  114. 


[March, 


uninjured  for  storage  by  the  codling  moth  of  either  brood)  were 
as  follows : 

TABLE  33.— PERCENTAGE  OF  TOTAL  CROP  UNINJURED   FOR  STORAGE  BY 
CODLING  MOTH,  BEN  DAVIS,  1904 


Treatment. 

Both  broods. 

1.  Paris  green,  %  Ib.  to  50  gal.,  with  lime  

34.75 

2.  Paris  green,  %  Ib.  to  50  gal.,  with  Bordeaux  

51.60 

3.  Arsenate  of  lead  

45  42 

4.  Arsenate  of  lead,  double  strength  

55.04 

5.  Check  —  no  late  spraying  

21  26 

6.  Paris  green,  ^  Ib.  to  50  gal.,  with  dilute  Bordeaux.  . 

53.38 

Marked  results  were  secured  from  the  spraying  under  every 
treatment.  The  double  strength  arsenate  of  lead  gave  the  best 
results,  though  the  Paris  green  in  combination  with  dilute  Bordeaux 
resulted  in  the  saving  of  nearly  as  much  fruit.  Owing  to  the  fact 
that  a  somewhat  smaller  percentage  of  the  crop  fell  before  maturity, 
the  tree  sprayed  with  Paris  green  and  dilute  Bordeaux  gave  a 
slightly  higher  percentage  of  fruit  suitable  for  storage  than  the  tree 
sprayed  with  Paris  green  and  standard  Bordeaux.  Both  trees 
yielded  a  much  larger  percentage  of  storage  fruit  than  the  tree 
sprayed  with  Paris  green  and  lime. 

SUMMARY  OF  RESULTS  FOR  THREE  YEARS 

In  order  to  present  in  condensed  form  the  results  of  the  experi- 
ments in  late  spraying  for  the  control  of  the  codling  moth  in  1902, 
1903  and  1904,  the  following  tables  (34,  35  and  36)  are  intro- 
duced. The  percentages  given  for  1902  were  obtained  by  averag- 
ing the  percentages  for  the  two  varieties. 


TABLE  34.— PERCENTAGE  OF  CROP  WHICH  PELL  BEFORE  MATURITY 


Treatment. 

1902. 

1903. 

1904. 

Ave. 

1 

Paris  green,  %  Ib.  to  50  gal.,  with  lime  

30.46 

33.46 

25.49 

29.80 

2a. 

?,h 

Paris  green,  %  Ib.  to  50  gal.,  with  lime  

46.31 

28  '.64 

2(V.  47 

.... 

8 

Arsenate  of  lead  

15.31 

35.83 

23.63 

24.92 

4. 

Arsenate  of  lead,  double  strength  

12.83 

30.72 

19.30 

20.95 

5 

28.02 

31.69 

r> 

Paris  green   with  dilute  Bordeaux 

17.42 

1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


419 


TABLE  35. — PERCENTAGE  OP  HAND-PICKED  CROP  INJURED  FOR  STORAGE 
BY  THE  CODLING  MOTH  (BOTH  BROODS) 


Treatmeut. 

1902. 

1903. 

1904. 

Ave. 

1.     Paris  green,  %  Ib.  to  50  gal.,  with  lime  

10.28 

21.55 

53.35 

28.39 

2a.  Paris  green,  %  Ib.  to  50  gal.,  with  lime  

8.98 

2b.  Paris  green,  with  Bordeaux  mixture  

19.18 

35.  16 

3.     Arsenate  of  lead  7  .  .  . 

8.87 

28.57 

44.52 

27.32 

4.     Arsenate  of  lead,  double  strength  

6.83 

20.62 

31.79 

19.74 

5.     Check  —  no  late  spraying  

35.94 

22.89 

68  87 

42  56 

6.     Paris  green,  with  dilute  Bordeaux.  .       .       . 

35.34 

TABLE  36. — PERCENTAGE  OF  TOTAL  CROP  UNINJURED  FOR  STORAGE  BY 
CODLING  MOTH  (BOTH  BROODS) 


Treatment. 

1902. 

1903. 

1904. 

Ave. 

1 

Paris  green,  /£  Ib.  to  50  gal.,  with  lime.  . 

61.94 

37.86 

34.75 

44.85 

2a 

Paris  green,  %  Ib.  to  50  gal.,  with  lime  

46.86 

?h 

Paris  green,  with  Bordeaux  mixture  

43.98 

51.60 

3 

Arsenate  of  lead  

77.18 

27.49 

45.42 

50  03 

4 

Arsenate  of  lead,  double  strength  

81.23 

40.69 

55.04 

58.98 

5. 

Check  —  no  late  spraying  

45.94 

21.26 

6 

Paris  green,  with  dilute  Bordeaux  

53.38 

It  will  be  seen  that  in  two  years  out  of  the  three,  the  benefits 
derived  from  the  late  spraying  were  very  marked,  except  in  the 
case  of  too  strong  a  mixture  of  Paris  green  which  caused  excessive 
dropping  of  the  immature  fruit.  The  average  results  for  the  three 
years  also  show  a  decided  advantage  in  favor  of  the  spraying.  Of 
the  different  spraying  mixtures  used  each  of  the  three  years,  the 
double  strength  arsenate  of  lead  gave  the  best  average  results, 
though  for  the  two  years  in  which  Paris  green  was  used  in  com- 
bination with  standard  Bordeaux  mixture,  this  material  gave  fully 
as  good  average  results  as  the  arsenate  of  lead.  Paris  green  was 
used  in  combination  with  dilute  Bordeaux  mixture  only  one  year. 
The  net  results  were  slightly  superior  to  those  obtained  by  the  use 
of  Paris  green  with  standard  Bordeaux,  though  this  difference  was 
probably  due  to  a  slight  variation  in  the  severity  of  the  attack  upon 
the  different  trees  rather  than  to  a  difference  in  the  real  efficiency 
of  the  two  mixtures. 


INVESTIGATIONS  IN  1906. 

The  investigations  in  reference  to  spraying  for  the  second  brood 
of  the  codling  moth  in  1901,  1902,  1903  and  1904  were  conducted 
in  the  University  orchard  at  Urbana,  where  the  codling  moth  was 


420 


BULLETIN  No.  114. 


[March, 


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1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


421 


abundant,  but  where  very  few  trees  of  the  same  variety  were  avail- 
able for  the  work.  While  the  results  showed  decided  average  bene- 
fits from  the  spraying,  it  was  thought  best  to  supplement  this  work 
by  a  test  conducted  on  a  larger  scale  in  one  of  the  more  distinctively 
apple-producing  regions  of  the  state,  and  to  include  the  use  of  a 
larger  number  of  different  mixtures.  Accordingly,  in  June,  1906, 
arrangements  were  made  for  carrying  on  such  a  test  in  the  orchard 
of  W.  H.  Perkins,  near  Quincy,  Adams  Co.  A  block  of  Ben  Davis 
trees,  fourteen  years  old,  was  selected,  and  divided  into  twelve  plats. 
Each  plat  consisted  of  three  rows  of  five  trees  each,  so  that  a  plat 
contained  fifteen  trees,  except  in  cases  where  one  or  two  trees  were 

— -  A/  — 


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which 


DIAGRAM  OF  EXPERIMENTAL,  BLOCK  AT  QUINCY,  1906. 

missing.  The  trees  had  been  sprayed  twice  in  the  spring,  and  were 
carrying  a  fair  crop  of  fruit.  In  the  late  spraying  the  various  plats 
were  treated  as  follows  : 

I.  Paris  green  J4  lb.,  lime  4  lb.,  water  50  gal.     Five  applications. 
2..  Paris  green  J4  lb.,  lime  4  lb.,  copper  sulphate  4  lb.,  water  50  gal.     Five 
applications. 

3.  Arsenate  of  lead  (double  strength)  made  from  lead  acetate  25  oz.,  soda 

afsenate  10  oz.,  water  50  gal.    Five  applications. 

4.  Check  —  no  late  spraying. 

5.  Commercial  arsenate  of  lead  2  lb.,  water  50  gal.     Five  applications. 

6.  Commercial  arsenate  of  lead  i  lb.,  Paris  green  J4  lb.,  lime  4  lb.,  water 

50  gal.    Five  applications. 

7.  Commercial   arsenate   of   lead   2   lb.,    lime   4   lb.,   copper    sulphate   2    lb., 

water  50  gal.    Five  applications. 

8.  Check'  —  no  late  spraying. 


422  BULLETIN  No.  114.  [March, 

9.  Paris  green  %  lb.,  lime  4  lb.,  copper  sulphate  2  lb.,  water  50  gal.     Five 
applications. 

10.  Paris  green  J4  lb.,  lime  4  lb.,  copper  sulphate  2  lb.,  water  50  gal.     Three 

applications. 

11.  Commercial   arsenate   of   lead   2   lb.,   lime  4   lb.,   copper   sulphate   2   lb., 

water  50  gal.     Three  applications. 

12.  Check — no  late  spraying. 

The  plats  receiving  five  applications  were  sprayed  July  10  or  n, 
20,  August  T,  17,  and  29,  while  those  receiving  three  applications 
were  sprayed  July  n,  20,  and  August  i.  The  entire  plat  was 
sprayed  in  each  case,  but  records  were  kept  regarding  the  product 
of  only  three  trees  in  each  plat.  Except  where  vacancies  occurred 
rendering  such  selection  impossible,  these  trees  were  in  the  middle 
of  the  plat.  The  accompanying  diagram  shows  the  arrangement  of 
the  plats  and  the  location  of  the  trees  selected  for  the  records. 

July  19  and  20  all  windfalls  were  gathered  from  under  the  se- 
lected trees,  and  a  complete  record  was  kept  of  all  apples  which  fell 
from  these  trees  after  that  time,  as  well  as  of  all  hand-picked  fruit 
gathered  at  the  harvest,  October  5  to  10.  Both  windfalls  and  hand- 
picked  fruits  were  sorted  on  the  basis  of  codling  moth  injuries, 
though  no  records  were  kept  regarding  the  point  of  entrance  of  the 
worms  nor  the  brood  to  which  the  various  worms  belonged.  The 
results  are  given  in  Table  37. 

These  figures  show  that  in  general  the  attack  of  the  codling  moth 
was  not  severe,  and  that  it  varied  in  severity  in  different  plats  under 
the  same  treatment.  The  three  check  plats  showed  wider  differences 
among  themselves  than  any  of  the  various  sprayed  plats.  When  the 
highest  percentage  of  injury  to  the  total  crop  in  a  check  plat  is  only 
8.57,  and  the  .difference  betwen  two  check  plats  is  4.58,  it  is  impos- 
sible for  the  results  of  spraying  to  appear  very  marked,  or  for  any 
definite  conclusions  to  be  drawn  regarding  the  relative  efficiency  of 
various  mixtures.  When  so  small  a  percentage  of  the  fruit  is  at- 
tacked, spraying  for  the  second  brood  of  the  codling  moth  would 
not  be  attended  with  financial  profit. 

WORK  AT  GRIGGSVILLE 

In  addition  to  the  test  conducted  in  the  commercial  orchard  near 
Quincy  in  1906,  a  few  trees  in  the  orchard  of  John  Sawdon,  near 
Griggsville,  Pike  Co.,  were  sprayed  with  special  reference  to  the 
second  brood  of  the  codling  moth,  and  detailed  records  kept  regard- 
ing the  extent  of  codling  moth  injuries  to  the  product.  Six  trees 
were  selected  which  had  been  sprayed  with  Bordeaux  mixture  and 


1907.' 


SPRAYING  FOR  THE  CODLING  MOTH. 


423- 


Paris  green,  April  25,  May  14,  and  21,  for  the  scab  and  first  brood 
of  codling  moth,  the  last  two  applications  being  made  after  the  petals 
had  fallen.  Four  other  trees  were  selected  which  had  received  no 
early  applications.  These  trees  were  divided  into  five  lots  of  two 
trees  each.  Three  of  these  lots  were  sprayed  five  times  for  the  sec- 
ond brood  of  the  codling  moth,  the  dates  of  application  being  July 
14,  21,  August  2,  15,  and  30.  The  full  treatment  of  the  various  lots 
for  the  entire  season  was  as  follows : 

1.  Three  early  applications  of  Bordeaux  and  Paris  green:    five  late  applica- 

tions of  Paris  green,  y\  Ib.  to  50  gal.,  with  dilute  Bordeaux  mixture. 

2.  Three  early  applications  of  Bordeaux  and  Paris  green ;    five  late  applica- 

tions of  commercial  arsenate  of  lead,  2  Ib.  to  50  gal. 

3.  'Three  early  applications  of  Bordeaux  and  Paris  green.  No  later  treatment. 

4.  No  early  spraying.    Five  late  applications  of  Paris  green,  %  Ib.  to  50  gal., 

with  dilute  Bordeaux  mixture. 

5.  Check — no  spraying  whatever. 

The  ground  under  the  trees  was  cleared  of  all  windfalls  July  14 
and  1 6,  and  complete  records  were  kept  regarding  all  apples  falling 
after  this  preliminary  clearing.  Table  38  gives  the  results  of  the  ex- 
amination of  these  windfalls  in  reference  to  codling  moth  injuries. 

TABLE  38.— EXAMINATION  OF  WINDFALLS,  GRIGGSVILLE,  1906 


No.  1. 

No.  2. 

No.  3. 

No.  4 

No.  5. 

Sound  ,  

284 

305 

205 

273 

39 

Injured  by  first  brood-  codling  moth: 
Entering  at  calyx  

189 

106 

177 

392 

387 

Entering  at  stem  

11 

1 

10 

6 

9 

Entering  at  side  

42 

33 

45 

57 

42 

Total  injured  by  first  brood  codling  moth 
Injured  by  second  brood  codling  moth: 
Entering  at  calyx  

242 
311 

140 
251 

232 
343 

455 
468 

438 
449 

Entering  at  stem  

25 

12 

43 

22 

28 

Entering  at  side  

65 

47 

117 

65 

128 

Total  injured  by  second  brood  codling 
moth  .  ,  

401 

310 

503 

555 

605 

Otherwise  injured  

739 

467 

707 

721 

2135 

Total  number  of  windfalls  

1666 

1222 

1647 

2004 

3217 

Percentage  of  windfalls  which  were  sound. 
Percentage  of   windfalls  injured    by   first 
brood  codling  moth  

17.04 

14.52 

24.95 
11  45 

12.44 
14.08 

13.12 

22  25 

1.22 
13.61 

Percentage  of  the  windfalls  injured  by  first 
brood  codling  moth,  in  which  the  worm 
entered  at  the  calyx  

78.09 

75.71 

76.29 

86.15 

88.35 

Percentage  of  windfalls  injured  by  second 
brood  codling  moth  

24.07 

25  .  36 

30.54 

22.70 

18  80 

Percentage  of  the  windfalls  injured  by  sec- 
ond brood  codling  moth,  in  which  the 
worm  entered  at  the  calyx  

77.55 

80.96 

68.19 

84.32 

74.21 

424 


BULLETIN  No.  114. 


[March, 


Eight  of  the  trees  in  this  experiment  carried  so  much  fruit  that 
thinning  became  necessary  in  order  to  prevent  breaking  of  the  limbs. 
This  thinning  was  done  September  3  and  4.  The  apples  were  re- 
moved without  selection,  but  were  all  examined  later  in  reference 
to  codling  moth  injuries,  and  the  results  recorded.  It  is  impossible 
to  determine  how  much  of  this  fruit  would  have  fallen  had  it  not 
been  thinned,  and  therefore  impossible  to  determine  which  treat- 
ment would  have  resulted  in  the  retaining  of  the  highest  percentage 
of  the  total  crop  on  the  trees  until  the  final  harvest,  had  thinning 
been  unnecessary. 

The  hand-picked  fruit  was  gathered  October  19  to  22,  and  sorted 
on  the  basis  of  codling  moth  injuries.  All  specimens  showing  indi- 
cations of  the  work  of  the  codling  moth  were  cut  open  to  determine 
the  extent  of  the  injury.  The  record  of  this  examination  is  given 
in  the  following  tables. 

TABLE  39. — EXAMINATION  OF  HAND-PICKED  FRUIT  FROM  TREES  SPRAYED 
FOR  CODLING  MOTH,  GRIGGSVILLE,  1906 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

Total  number  of  apples  

3695 

3546 

4452 

3881 

2999 

Visibly  attacked  by  second  brood   codling 
moth  at  calyx: 
Injured  for  storage  

152 

71 

77 

226 

88 

Worm  found  in  apple  

40 

17 

16 

29 

7 

Worm  gone  tointeriorbutnot  found: 
Fruit  badly  damaged  

72 

48 

59 

'   163 

70 

Fruit  not  badly  damaged  

40 

.6 

2 

34 

11 

Uninjured  for  storage  (worm    stopped 

20 

20 

6 

20 

4 

Visibly  attacked  by  second  brood  codling 
moth  at  stem: 
In  j  ured  for  storage  

15 

0 

13 

10 

12 

Worm  found  in  apple  

5 

0 

3 

6 

0 

Worm  gone  to  interior  but  not  found: 
Fruit  badly  damaged  

9 

0 

8 

4 

11 

Fruit  not  badly  damaged  

1 

0 

2 

0 

1 

Uninjured  for  storage  (worm   stopped 
near  surface)  

5 

1 

4 

2 

0 

Visibly  attacked  by  second  brood  codling 
moth  at  side: 
Injured  for  storage  

105 

26 

78 

57 

32 

Worm  found  in  apple  

19 

6 

11 

6 

6 

Worm  gone  to  interior  but  not  found: 
Fruit  badly  damaged  

55 

19 

63 

50 

24 

Fruit  not  badly  damaged  

31 

1 

4 

1 

2 

Uninjured  for  storage  (worm  stopped 
near  surface)  

52 

22 

29 

24 

23 

Injured  bv  first  brood  codling  moth.  ........ 

Entering  at  calyx  

76 

6 

4 

12 

3 

Entering  at  stem.                

1 

0 

0 

0 

0 

Entering  at  side  

35 

2 

2 

2 

1 

Not  visibly  attacked  by  codling  moth  

3234 

3398 

4239 

3528 

2836 

1907.] 


SPRAYING  FOR  THE  CODLING  MOTH. 


425 


TABLE  40. — SUMMARY  OF  EXAMINATION  OF  HAND-PICKED  FRUIT  FROM 
TREES  SPRAYED  FOR  CODLING  MOTH,  GRIGGSVILLE,  1906 


»• 

No.  i 

No.  2 

JNo.  3 

JNo.  4 

No.  5 

3695 

3546 

4452 

3881 

2999 

"Visibly  attacked  by  second  brood  codling 
moth  

349 

140 

207 

339 

159 

Injured  for  storage    by  second    brood 
codling  moth  

272 

97 

168 

293 

132 

W^orm  found  in  apple  

64 

23 

30 

41 

13 

Worm    gone    to    interior  but    not 
found: 
Fruit  badly  damaged  

136 

67 

130 

217 

105 

Fruit  not  badly  damaged  

72 

7 

8 

35 

14 

Uninjured  .for   storage  (worm  stopped 
near  surface)  

77 

43 

39 

46 

27 

Injured  by  first  brood  of  codling  moth  

112 

8 

6 

14 

4 

Not  visibly  attacked  by  codling  moth  

3234 

3398 

4239 

3528 

2836 

TABLE  41. — PERCENTAGE  OF  HAND-PICKED  FRUIT  INJURED   BY  CODLING 
MOTH,  GRIGGSVILLE,  1906 


No.  1 

No.  2 

No.  3 

No.  4 

No.  5 

Percentage     visibly    attacked    by    second 
brood  codling  moth  

9.44 

3.94 

4.64 

8.73 

5.30 

Percentage  injured  for   storage  by  second 
brood  codling  moth  

7.36 

2.73 

3.77 

7.55 

4.40 

Percentage  in  which  second  brood  worms 
stopped  near  surface  

2.08 

1.21 

.87 

1.18 

.90 

Percentage  injured  by  first  brood  only  
Percentage  uninjured  for  storage  by  cod- 
ling moth  (both  broods)  

3.03 
89.61 

.22 
97.05 

.13 

96.10 

.36 

92.09 

.13 

95.47 

Percentage  of  apples  attacked  by  second 
brood  in  which  worms  stopped  near  sur- 
face   

22.06 

30.71 

18.84 

13.56 

16.98 

Percentage  of  the  apples  injured  for  stor- 
age by  second  brood  codling  moth,  which 
were  entered  at  ralvx  

55.88 

73.19 

45.83 

77.13 

66.66 

It  will  be  seen  that  the  percentage  of  hand-picked  fruit  injured 
by  the  codling  moth  was  in  every  case  comparatively  small.  The 
highest  percentage  of  injury  was  in  lot  No.  i,  which  received  both 
early  and  late  applications.  The  trees  in  this  lot  were  not  as  thor- 
oughly sprayed  in  1904  as  were  those  in  the  other  lots,  and  were 
badly  infested  that  year.  None  of  the  trees  in  the  orchard  were 
sprayed  in  1905.  It  seems  probable  that  the  trees  in  lot  No.  i  were 
more  severely  attacked  in  1906  than  were  those  in  the  other  lots. 
They  must  certainly  have  been  more  severely  attacked  than  the  check 
trees,  for  in  spite  of  the  spraying  they  showed  a  higher  percentage 
of  injury. 

On  account  of  the  necessity  of  thinning  the  fruit,  it  is  impossible 
to  compare  the  results  of  the  various  treatments  on  the  basis  of 


426 


BULLETIN  No.  114. 


[March, 


"percentage  of  total  crop  remaining  on  trees  uninjured  till  the 
harvest."  Under  these  circumstances  it  is  probable  that  the  fairest 
way  to  compare  the  results  of  the  different  treatments  is  on  the 
basis  of  the  percentage  of  the  total  crop  (including  windfalls, 
thinned  and  hand-picked  fruit)  injured  by  the  codling  moth.  The 
data  for  determining  these  percentages  and  the  percentages  them- 
selves are  given  in  Table  42. 


TABLE  42. — EXAMINATION  OF  TOTAL  CROP  FROM  TREES  SPRAYED  FOR 
CODLING  MOTH,  GRIGGSVILLE,  1906 


No.  1 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

Windfalls  

1666 

1222 

1647 

2004 

3217 

Thinned  fruit  

1507 

1368 

2575 

1950 

1556 

Hand-picked  (mature  fruit)  

3695 

3546 

4452 

3881 

2999 

Total  crop  

6868 

6136 

8674 

7835 

7772 

Injured  by  first  brood  codling  moth: 
Entering  at  calyx  

371 

135 

231 

489 

414 

Entering  at  stem  

16 

1 

13 

7 

9 

Entering  at  side  

97 

43 

73 

70 

55 

Total  injured  by  first  brood  codling  moth 

Injured  by  second  brood  codling  moth: 
Entering  at  calyx  

484 
596 

179 
392 

317 
618 

566 
879 

478 
687 

Entering  at  stem  

49 

18 

90 

42 

64 

Entering  at  side  

221 

110 

264 

161 

210 

Total  injured  by  second  brood  codling 
moth  

866 

520 

972 

1082 

961 

Not  visibly  attacked  by  codling  moth  

5518 

5437 

7385 

6187 

6333 

Percentage  of  total  crop  injured  by  first 
brood  codling  moth  

7  04 

2  91 

3.65 

7.22 

6.17 

Percentage  of  total  crop  injured  by  second 
brood  codling  moth  

12.61 

8.47 

11.20 

13.81 

12.36 

Percentage  of  total  crop  injured  by  codling 
moth  (both  broods)  

19  65 

11  38 

14  85 

21  03 

18.53 

Percentage  of  the  apples  injured  by  first 
brood  codling  moth,  in  which  the  worm 
entered  at  the  calyx  

76.65 

75  42 

72.87 

86.39 

86.61 

Percentage  of  the  apples  injured  by  second 
brood  codling  moth,  in  which  the  worm 
entered  at  the  calyx  

68.82 

75.38 

63  58 

81.23 

71.48 

The  smallest  percentage  of  injured  fruit  was  from  lot  No.  2, 
which,  in  addition  to  the  early  spraying,  received  five  late  applica- 
tions of  arsenate  of  lead.  Lot  No.  3,  which  received  only  the  early 
applications,  showed  only  slightly  more  injury  than  this  lot.  Lot 
No.  4,  which  received  only  the  late  applications  and  lot  No.  I,  which 
was  sprayed  both  early  and  late,  showed  more  injury  than  the  un- 


1907.]  SPRAYING  FOR  THE  CODLING  MOTH.  427 

sprayed  lot  (No.  5.)  Under  the  conditions  existing  in  this  orchard 
in  1906,  when  the  general  attack  of  the  codling  moth  was  compara- 
tively slight,  none  of  the  spraying  for  the  second  brood  gave  results 
which  would  warrant  the  expense  of  the  operation. 

It  is  worthy  of  notice  that  a  very  large  percentage  of  the  apples 
injured  by  the  second  brood  of  the  codling  moth  were  entered  at 
the  calyx.  The  records  of  the  previous  experiments  show  that  a 
similar  condition  existed  at  Urbana  in  1903,  and  that  the  results  of 
the  late  spraying  were  that  year  much  less  favorable  than  in  years 
when  a  smaller  proportion  of  the  injured  apples  were  entered  at 
the  calyx.  The  records  for  four  years  show  wide  variations  in  the 
percentage  of  the  apples  injured  by  the  second  brood  of  the  codling 
moth  which  were  entered  at  the  calyx  end.  Records  on  this  point 
for  the  four  years  were  kept  in  regard  to  the  windfalls  only.  Con- 
sidering all  the  apples  which  fell  after  about  July  15  (the  date  vary- 
ing in  different  years)  from  the  trees  under  observation  which  had 
received  the  usual  early  spraying  but  no  late  spraying,  the  per- 
centages of  the  fruits  injured  by  second  brood  codling  moth  larvae 
in  which  the  worm  had  entered  at  the  calyx,  were,  for  the  different 
years,  as  follows : 

TABLE  43.— PERCENTAGE  OF  INJURED  FRUITS  ENTERED  AT  CALYX 


Year. 

1902. 

1903. 

1904. 

1906. 

Number  of  injured  specimens 

sin 

4.70 

^19 

KA'i 

Percentage  entered  at  calyx  

44  90 

79  (\1 

47  fi^ 

us   :<) 

This  indicates  that  the  habits  of  the  second  brood  larvae  may  be 
different  in  different  years,  and  that  the  poorer  results  of  the  late 
spraying  in  1903  and  1906  as  compared  with  1902  and  1904  may 
have  been  due  partly  to  this  difference  in  the  habits  of  the  worms. 

CONCLUSIONS 

1.  Spraying  for  the  first  brood  of  the  codling  moth  may  be  com- 
menced as  soon  as  most  of  the  petals  have  fallen  from  the  trees,  and 
the  first  application  should  be  completed  within  seven  days  from 
that  time. 

2.  The  method  employed  in  this  first  application  should  be  one 
which  will  result  in  the  lodging  of  considerable  spraying  material 
within  the  calyx  cavities  of  the  highest  possible  percentage  of  the 
young  apples.     A  comparatively  large  amount  of  material  applied 


428  BULLETIN  No.  114.  [March, 

under  high  pressure  through  fine  nozzles  is  most  likely  to  secure 
the  desired  end,  though  if  the  amount  is  excessive,  russeting  of  the 
fruit  and  injury  to  the  foliage  may  follow. 

3.  While  one  thorough  application  at  the  proper  time  will  re- 
sult in  the  saving  of  a  large  percentage  of  the  fruit  that  would 
otherwise  be  injured  by  the  first  brood  of  the  codling  moth,  it  is 
probable  that  at  least  one  additional  application  for  the  first  brood 
should  be  made,  and  the  investigations  in  1902  indicate  that  one  or 
two  further  applications  may  result  in  the  saving  of  still  more  fruit. 

4.  It  is  possible  to  kill  many  of  the  second  brood  larvae  of  the 
codling  moth  by  means  of  a  poisonous  spray  applied  late  in  the 
season. 

5.  The  habits  of  the  second  brood  larvae  of  the  codling  moth 
vary  greatly  in  reference  to  the  point  of  entrance  into  the  apple. 

6.  Late  spraying  for  the  second  brood  of  the  codling  moth  is 
more  effective  against  the  worms  which  attack  the  apples  at  the 
side  than  against  those  which  seek  entrance  at  the  calyx.     There- 
fore, when  a  large  proportion  of  the  second  brood  larvae  enter  the 
apples  by  way  of  the  calyx,  the  late  spraying  is  less  effective  in 
saving  the  crop  than  is  the  case  when  a  larger  proportion  of  the 
larvae  attack  the  apples  at  the  side. 

7.  The  thoroughness  of  the  early  applications  of  spraying  ma- 
terial for  the  first  brood  of  the  codling  moth  may  have  a  marked 
influence  upon  the  control  of  those  larvae  of  the  second  brood  which 
seek  entrance  at  the  calyx. 

8.  If  the  late  spraying  is  not  commenced  until  after  the  first 
worms  of  the  second  brood  have  entered  the  apples,  but  an  applica- 
tion is  made  before  these  worms  penetrate  deeply  into  the  fruit, 
many  of  the  worms  which  have  entered  the  sides  of  the  apples  may 
be  killed  by  the  spray  applied  after  they  have  entered. 

9.  Since  new  larvae  of  the  second  brood  may  continue  to  appear 
for  a  period  of  four  or  five  weeks,  repeated  applications  of  spraying 
material  are  necessary,  and  there  will  usually  be  some  larvae  which 
have  not  been  destroyed  by  previous  applications,  but  which  are 
feeding  just  beneath  the  surface  of  the  fruit  at  the  time  an  applica- 
tion is  made.    There  may  therefore  be  many  apples  at  the  harvest 
which  have  been  attacked  by  the  codling  moth,  and  slightly  blem- 
ished before  the  worms  were  killed. 

10.  Apples  in  which  codling  moth  larvae  have  been  killed  close 
to  the  surface  are  but  slightly  blemished,  and  keep  in  cold  storage 
almost  as  well  as  do  specimens  absolutely  without  blemish. 


too?.]  SPRAYING  FOR  THE  CODLING  MOTH.  429 

11.  The  use  of  a  simple  mixture  of  Paris  green  and  water  is 
not  to  be  recommended  for  the  late  spraying  of  apple  trees,  because 
there  is  danger  of  injury  to  the  foliage  and  excessive  dropping  of 
the  fruit  by  reason  of  injury  to  the  stems. 

12.  Even  when  used  with  lime,  Paris  green,  especially  if  used 
in  quantities  greater  than  y^  Ib.  to  50  gallons,  is  likely  to  cause  ex- 
cessive dropping  of  the  fruit.     However,  when  used  in  combination 
with  Bordeaux  mixture,  the  Paris  green  does  not  have  this  unde- 
sirable effect. 

13.  Paris  green  used  in  combination  with  Bordeaux  mixture, 
at  the  rate  of  y^  Ib.  to  50  gallons,  and  arsenate  of  lead  made  from 
25  oz.  of  lead  acetate  and  10  oz.  of  soda  arsenate  to  50  gallons,  are 
about  equally  efficient  in  late  spraying  for  the  control  of  the  second 
brood  of  the  codling  moth. 

14.  Late  spraying  for  the  second  brood  of  the  codling  moth  is 
much  more  effective  some  years  than  others. 

15.  When  the  attack  of  the  second  brood  of  the  codling  moth 
is  not  severe,  late  spraying  for  the  control  of  this  brood  will  not 
result  in  sufficient  benefit  to  pay  for  the  expense  of  the  operation. 
If,  however,  an  orchard  is  to  be  sprayed  with  Bordeaux  mixture 
late  in  the  season  for  the  control  of  fungous  diseases,  it  will  be  ad- 
visable to  add  Paris  green  to  the  mixture  for  the  sake  of  its  effect 
upon  the  second  brood  of  the  codling  moth. 


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